It is difficult to overstate Kautsky’s importance and influence as a thinker. His role was most diverse: among other things, he prepared several of Marx’s manuscripts and letters for publication (such as Theories of Surplus Value, generally viewed as Volume IV of Capital), popularized Marxist ideas, and brought them to a much wider international audience than Marx or Engels was ever in a position to reach. Between 1883 and 1918, he wrote nearly forty books, about five hundred journal articles, and well over three hundred newspaper articles. His work was translated into more than twenty languages. Most important, following the runaway success of his commentary on the SPD’s Erfurt Program of 1891 (available in abridged form in English as The Class Struggle), he rose to prominence as the theorist of the “Bebel-Kautsky” tendency of the Second International, which was the driving force behind that organization’s strategy and tactics.

The international reach of this tendency was primarily achieved through Die Neue Zeit, the immensely popular Marxist theoretical weekly that Kautsky edited until 1917. This journal was studied and discussed far beyond the boundaries of the German Empire. In Russia, Kautsky was viewed as something of an “honorary Bolshevik” on account of him often taking sides with the Bolshevik faction of the Russian Social Democratic Labor Party [RSDLP] on matters of strategy and tactics in that country. His writings on Russia reveal him as an inspiration behind the Russian Revolution of 1917. After all, Kautsky had been a consistent advocate of an alliance between the revolutionary proletariat and the peasantry and firmly against any such agreements with the liberal bourgeoisie in Russia. This “anti-agreementist” approach informed the Bolshevik success between February and October 1917. As Lih has conclusively shown, the October Revolution was a not a repudiation of the February Revolution, but its continuation.

Moreover, despite ongoing efforts to create a gulf between Lenin, the alleged vanguardist insurrectionist, and Kautsky, the purported parliamentarian socialist, the October Revolution was actually constitutional, in that it reflected a shift in the soviets’ outlook regarding how best to assert their de facto sovereignty after the collapse of Tsarism, as they moved toward the recognition that the Provisional Government could not represent their interests and so had to be replaced. A crucial factor in this development was the Bolsheviks’ strong “anti-agreementist” message. Following Kautsky, they consistently called for no illusions in the bourgeois Provisional Government and for support for a new revolutionary authority based on the workers and peasants. Eventually, this message won the day. Looking on from Germany, however, Kautsky saw the October Revolution as a form of coup and wrote several vehement critiques of the early Russian state. But this should not obscure the fact that Kautsky, “when he was a Marxist,” embodied the continuation of Marxism as it became a historical reality for millions of people.

Today, however, this picture is radically different. To the extent that Kautsky is remembered at all beyond the “renegade” justifiably pilloried in Lenin’s The Proletarian Revolution and the Renegade Kautsky, his name is inexorably bound up with accusations of flattening, debasing, vulgarizing, or removing the dialectical essence of Marxism. As I explore in more detail in the book, however, such charges result from the absence of serious engagement with his work. In turn, this absence can be traced back to the historically conditioned marginalization of his ideas in the twentieth century.

I identify three schools of Kautsky interpretation responsible for the disdain shown toward his life’s work: the Eastern bloc’s bastardization of Marxism (and its Trotskyist mirror image), Western pro-capitalist Cold War historiography and the neo-Hegelian interpretation of Marxism. Notwithstanding the differences between these three schools, they unanimously view Kautsky as a fatalistic, mechanistic thinker who had no positive impact on the Russian Revolution of 1917. Moreover, for the neo-Hegelian interpretation in the West, and historiography in the East in particular, Kautsky’s purported fatalistic passivity was premised on a misreading of Marx’s thought. This interpretation then fed into the ideas of the post-1956 New Left, which claimed that Engels was the first vulgarizer of Marxism, with Engelsism-Kautskyism allegedly leading to Stalinism.

During my research, it became clear to me that the “vulgarization” thesis did not stand up to scrutiny. A closer look at Kautsky’s voluminous writings on political economy, history, democracy, revolutionary strategy, and so on illustrate just how unfairly the “pope of Marxism” has been treated by subsequent history. From today’s perspective, several of Kautsky’s conclusions during the zenith of his theoretical output are clearly problematic: the idea that the socialist revolution is primarily a national event, his identification of a qualitatively “new” phase of imperialism in the 1890s, his lifelong tendency to prioritize unity to the occasional neglect of principle, and so forth. However, I do not believe that these amounted to a — conscious or otherwise — flattening of Marxism. Rather, they reflected the man engaging critically with the unfinished intellectual output of his forebears in a rapidly changing world. Kautsky never merely recycled and repeated the teachings of Marx and Engels. He was an original thinker in his own right, seeking to apply the methods of his heroes to his own time. On occasion, this entailed updating their prognoses and vindicating others. In this sense, Kautsky was being a good Marxist.

Once again, the notion that the younger Kautsky hedged his bets on the need for revolution — or, in the words of biographer Dick Geary, that Kautsky’s “preconditions” for revolutionary upheaval were so “exhaustive as to justify inaction even (or perhaps particularly) in revolutionary situations”  — is very much a product of the false dismissal of his thought as a non- or anti-revolutionary thinker, as I described earlier.

There are two things I find particularly fascinating about the debates surrounding the Erfurt Program in the early 1890s. The first is that it becomes apparent just how seriously the SPD leadership went about formulating the program and its theoretical basis. The point of departure was not a shopping list of popular demands or ideas in fashion at a given point in time, but rather an outline of how the SPD would come to power as part of the complete dissolution of the reactionary Kaiserreich. This struggle for working-class rule was viewed as a step toward the “abolition of class rule and of classes themselves, for equal rights and equal obligations for all, without distinction of sex or birth.” The Erfurt program thus did not shy away from proclaiming ideas such as arming the people, dissolving the monarchy, and separating church and state.

Second, it becomes apparent just how central Engels was in bringing the program into existence as an unashamedly Marxist one in the tradition of the earlier programs penned by him and Marx, such as the Communist Manifesto in 1848 and the Program of the Parti Ouvrier in 1880. From London, Engels fired off articles, commented on the program drafts, and sought to influence leading figures such as Kautsky and August Bebel to bring about the defeat of state-socialist illusions within the party. I argue that Engels’s main concern was to ensure that the party committed itself to a democratic-republican approach to the transformation of state and society — something that can also be found in the best of Kautsky’s writings.

The Erfurt Program’s focus on democratic demands was twofold. On the one hand, the emphasis on democracy was to ensure that the German working class could organize and thrive in organizational and theoretical terms. In one of Kautsky’s more memorable phrases, political freedom is the “light and air” of the working class, with aspirations to transform society in its own image. It is worth recalling that the SPD was outlawed for more than a decade, and that in the 1890s there were several other unsuccessful attempts to ban it again. Precisely because of its programmatic commitment to the revolutionary overthrow of the state, the party did not take legality for granted, and its opponents did not take that legality lightly.

But this is certainly not the end of the matter: and here we return to the significance of Marxist republicanism I mentioned earlier. For Marx and Engels, the democratic republic was what Engels deemed the form for the dictatorship of the proletariat. In other words, in the fight for the democratic republic, the working class becomes a “class for itself” and comes to power. Drawing on the experience of the Paris Commune, the first workers’ government, Marx and Engels argued that this state was defined by several features, such as a single legislative and executive assembly, the regular elections of officials, including judges, recallability, workers’ wages for bureaucrats, the armed people, and so on. Many of these democratic demands were also present in the Erfurt program itself, which accounts for Engels’s enthusiasm.

Engels’s critique, which was not a criticism of the program as such, but of an earlier draft penned by Wilhelm Liebknecht, revolved around the absence of the democratic republic as a stated programmatic aim. Engels wrote: “The political demands of the draft have one great fault. It lacks precisely what should have been said. If all the ten demands were granted we should indeed have more diverse means of achieving our main political aim, but the aim itself would in no wise have been achieved.” Once again, the threat of illegality loomed large, and Engels argued that if the declaration of a democratic republic might place the party’s existence in jeopardy, then an alternative formulation would have to be found. Engels’s criticism, then, was not aimed at the focus on democratic demands or the overall structure of the program. He simply felt that the absence of an unambiguous proclamation of the goal that flows from the minimum demands of the program — working-class political power — would leave the door open to state-socialist misappropriation.

I think that the best way to answer these questions is to work backward: today, the minimum program is indeed largely misunderstood or forgotten. For a variety of historical reasons, the revolutionary content of the minimum section of programs such as the Communist Manifesto, the Erfurt Program, the program of the RSDLP in 1903, the program of the RSDLP(B) in 1917, etc., has been overlooked. This is particularly true in the Trotskyist tradition, which has a tendency to project ahistorically Leon Trotsky’s — methodologically completely different — The Death Agony of Capitalism and the Tasks of the Fourth International from 1938 onto the experience of the October Revolution, the writings of Marx and Engels, and so forth.

You mention Salvadori, but a whole host of writers take their cue from this approach: most important, perhaps, the esteemed historian Pierre Broué, author of a magisterial work on the German Revolution. A series of hollowed-out, minimal day-to-day demands is how most historians and activists generally view the minimum program today. But a closer look at its history underlines how we are looking at this program through the wrong end of the telescope.

This can again be explained with reference to the historical retreats of our movement in general — and to Kautsky’s legacy. As we know, SPD did eventually drift toward something more akin to the legalist, state-socialist approach that was attacked by Engels, Kautsky, and others. This gravitation entailed the steady erosion of German social democracy’s program, with the “minimum” demands gradually deemed too advanced or insufficiently popular for the masses. These increasingly transformed into “maximum demands,” with high politics and socialism pushed further into the future — a “distant guiding star,” in the apt words of Rosa Luxemburg. This was indeed a manifestation of a strategic no-man’s land — as was the Stalinist misappropriation of the minimum program to justify the politics of popular frontism and alliances with “progressive” bourgeois forces. But the point bears repeating that it was not the original conception of the minimum program in the minds of Marx, Engels, or Kautsky. We should not throw the baby out with the opportunist bathwater.

As you said at the outset, in my research, I follow Lenin’s interpretation of Kautsky as somebody who eventually came to renege on the revolutionary nature of his earlier outlook. In so doing, I draw on primary source material to show that Kautsky — or, rather, the “renegade Kautsky” — also played a pivotal role in reducing the minimum program of social democracy to a minimal program. Through a comparison of his republican writings from 1905 and 1918–1919, I demonstrate how Kautsky paints in “Marxist” gloss the decision of the SPD to enter an openly bourgeois government alongside the Catholic Centre Party and the Liberals in 1919. In my mind, this is one of the clearest manifestations of his collapse as a revolutionary thinker and a salient reminder that “Kautsky’s Marxism” should not be treated as a static and unchanging Weltanschauung, as is unfortunately too often the case in existing scholarship and on the Left. Kautsky never accounted for this shift from a rejection of bourgeois coalitionism and Millerandism to an embrace of it, but he must have been conscious of it on some level.

Kautsky’s response to the shock of Millerandism passed through several stages. In 1900, he drafted a resolution condemning socialist participation in bourgeois governments, which was adopted at the Paris Congress of the International that year. Interestingly, however, the resolution contained a key weakness. For although it unequivocally condemned socialist coalitionism in “normal circumstances,” it left the door open to such participation in extreme or catastrophic situations — such as perhaps during an invasion or occupation of a country. This caveat delighted the “revisionist” right wing of social democracy, who generally aimed for socialists to participate in holding office within the bourgeois state. Equally, it earned the condemnation of the Iskra editorial board, which referred to it not as the “Kautsky resolution,” but the “rubber [in Russian, kauchuk] resolution” — the a malleable and thus opportunist statement.

By the time of the SPD Congress in Dresden in 1903, however, Kautsky drafted a resolution on government participation that was free of all ambiguity and removed all references to extreme situations. Looking back on the 1900 resolution at the Dresden Congress, he noted: “Back then I did look to formulate the resolution in a way that turned against Millerand in principle, but which presented his behavior as a mistake, not a crime. I wanted to preserve the principled standpoint and yet pave the way for unity amongst the French.” (He was heckled and accused of opportunism for this.)

By the Amsterdam Congress of the International in 1904, which saw a fierce clash between the proponents of Marxism and the small minority trend in French socialism that was Millerandism, Kautsky was unwavering in his critique of some French socialists supporting taking office in a capitalist government in the name of “defending the republic” from right-wing reaction. The fallout prompted him to write the series “Republic and Social Democracy in France,” which is available in my book for the first time in English translation. The series is an extended critique of French “Possibilist” socialism for doing the dirty work of the bourgeoisie precisely because it had not won power. Its “defending the republic” thus amounted to protecting, and apologizing for, an aggressively anti-working-class bourgeois state.

Following Marx and Engels, Kautsky distinguished between the faux republicanism of the bourgeois French Third Republic (“the Empire without the Emperor”) and the proletarian republicanism of the short-lived Paris Commune. In so doing, he subjected the judicial, constitutional, military, electoral, and economic foundations of the Third Republic to a thoroughgoing critique, comparing and contrasting them to those of the Paris Commune. It is a work that shows him at his best — and provides another example of how wrong it is to see him as a passive thinker who possessed no theory of politics or revolution, and merely waited for the revolution to arrive like fruit ripening on a tree.

That is a difficult question. Answering it would require synthesizing, and building upon, the social-historical studies of the local SPD organizations that first became popular in the 1970s and 1980s and continue through to today, such as James Retallack’s Red Saxony.

As you allude to, the original idea was that the party and the working-class institutions would form an irreconcilable opposition to the existing state and instead develop their own organizations, education, and recreation: the building up of a state, as part of the preparation to run an alternative state themselves. From the perspective of socialist revolution, passivity within organizations striving for working-class hegemony is obviously far preferable to activity within bourgeois education, recreational, and sporting structures.

While it is difficult to distinguish between active and passive involvement, it is astounding just how widespread this “alternative culture” became. In fact, I do not think that the party could have grown to the extent that it did without these self-standing institutions as ways of organizing working-class life: for this reason alone, the SPD’s aspirations of organizing the working class as a class — not just in the workplace —  remains a model to be emulated. These SPD-run institutions were a world apart from the corporatized “services” run by modern bureaucratized, statist trade unions and labor parties for their “clients.”

What is more, it is no accident that some of the most influential Marxist thinkers, organizers, and parliamentarians emerged from within the SPD and the Second International: an ambitious and well-organized socialist counterculture creates the conditions for the blossoming of ideas, organizations, and leaders, as opposed to the often intellectually pitiful and narrow-minded careerists that tend to thrive in today’s emaciated labor movement.

That said, as the SPD and its various organizations grew, problems of organizational bureaucracy and institutional accountability of leaders did arise. I do not view this as an inevitable expression of Robert Michels’s “iron law of oligarchy” within large-scale political institutions, but I do think that the emergence of a well-remunerated, self-reinforcing, and technocratic officialdom is inseparable from the SPD’s political decline. More research needs to be devoted to this question, but as far back as the 1890s, critical voices were being raised at party congresses about the excessive pay received by officials and representatives. Noteworthy in this regard is that one significant omission from both the Erfurt Program and Engels’s criticisms of the original draft was the need for workers’ representatives to take an average worker’s wage.

It is certainly true that the war credits vote was not entirely unexpected: elements of the SPD parliamentary fraction had long been seeking to demonstrate the party’s ‘respectability’ by looking to vote for Reichstag naval bills and expansionist colonial adventures. As Jens-Uwe Guettel has shown, however, such pro-colonialist trends were kept in check by the party leadership and — much to the chagrin of these deputies — by the majority of the party membership.

What was so outrageous about the vote for war credits, however, was that it came to symbolize how the SPD had, for all its pledges of intransigent opposition, now become tied to the German state and its war aims. This was as true of the gung-ho “German victory” types (Alexander Parvus, Paul Lensch, Konrad Haenisch) on the former “far left” as it was of those like Kautsky, who were critical but sought to preserve party unity: and this meant unity within the framework of the so-called “fortress peace” [Burgfrieden] — i.e., unity with the Kaiser’s generals and the mainstream parties.

Clearly, it would have been preferable for the question of a party split to have been posed earlier — and ideally from within the party itself, instead of from the “original catastrophe” of the twentieth century. I think you are right that one way that the question of loyalty to the German state could have been posed is if, for example, the German electoral system had been more representative, making socialists entering into government more likely. One of the fascinating “what-ifs” of socialist history is how Kautsky, Bebel, et al. would have responded to the German revisionists playing footsie with the establishment parties in Germany for government posts and influence, like their counterparts in France. When it came to such endeavors in France, for instance, Kautsky favored those like Jean Jaurès being thrown out of the International, whereas Bebel abhorred such suggestions.

I suppose my answer would be threefold. First, I do not think it is fair to see Kautsky merely as a popularizer of Marxism: he was somebody who developed Marxist theory and politics for a mass international audience. As such, it is almost criminal that the Left has not seriously interacted with the rich material outlined in journals such as Die Neue Zeit, or newspapers such as the Leipziger Volkszeitung or Vorwärts. They are a veritable treasure trove of Marxist thought from a time when socialism amounted to some kind of “common sense” among the mass of the working classes in Europe.

Second, while my research is indeed “historical background” for debates within organizations that seem to be not only from a different time but a different world, getting the historical record straight is of immense importance. As a look at the excellent recent publication by David Brandenberger and Mikhail Zelenov makes clear beyond doubt, the so-called “Bolshevik” dismissal of the revolutionary Kautsky, “Second International Marxism,” and the SPD stems directly from the keen pen of Joseph Stalin in 1938, who set about counterposing the Russian “party of a new type” he was building in fierce opposition to the Second International and its parties. How ironic, then, that modern-day anti-Stalinist social democrats and Trotskyists have the same view of Bolshevism! History should matter to the Left — and we should base ourselves on the very best of our past, not our defeats.

Third, and relatedly, bad history begets bad politics — and vice versa. I think today’s Left has lost the huge ambition and the patient revolutionary realism of the Kautsky school and needs to rediscover it. Instead of seeking to build mass parties openly committed to developing an alternative proletarian culture within, and against, capitalism, a swath of semi-conspiratorial groups masquerading as “parties of a new type” compete to put out the most effective single-issue liberal campaigns, “broad” trade-union fronts, “parties not delimited between reform and revolution” (as Daniel Bensaïd put it), or the “policies that most Labour members want,” in order to recruit. In the name of the “transitional method,” the most minimal demands are blessed with a revolutionary significance that they do not possess.

When it comes to Kautsky concretely, I think there has not only been a welcome rediscovery of his ideas, but also a continuation of the distorted twentieth-century narrative. This is evinced by the current ahistorical portrayal of Corbynism or Bernie Sanders’s “democratic socialism” as a modern-day incarnation of Kautskyan strategy, or the idea that the Democratic “Squad” in Congress are acting in the spirit of the SPD’s parliamentarians in the Reichstag by exposing the corruption and hypocrisy of the ruling classes.

In my view, such appropriations of Kautsky’s legacy do a disservice even to the arch-revisionist Eduard Bernstein, who, after all, insisted on the necessity of building a workers’ party with — different variants of — a socialist program across his career. Now, it might be objected that the kind of revolutionary Marxism on which the SPD was founded in late-nineteenth-century Germany does not apply to today’s United States, where revolutionary ideas are thoroughly discredited, and thus activists should focus instead on focusing on building the bases of the US left around so-called popular demands such as a $15 minimum wage, Keynesian-type taxation policies, a Green New Deal, and so on. We often hear that the road to socialism is paved by mobilizing the masses around such “bread-and-butter,” commonsense demands. But if that were so, we would have arrived at socialism a century ago.

Although those US comrades currently citing Kautsky in order to peddle such politics obviously feel that they are shrewdly endowing their project with the authority of one of the most important names in the history of Marxism — the revolutionary project to bring the working class to power, no less — their doing so involves a dishonest historical falsification of the legacy of both the revolutionary Kautsky and the renegade who eschewed his earlier outlook.

I believe only the unification of Marxists into mass parties of class organization, in opposition to the capitalist state — along the lines of the early SPD — can bring about a serious and lasting breakthrough for the working-class movement internationally. That work needs to start immediately and not be postponed in the name of so-called “relevance” and immediate expediency. As things stand, this does indeed seem difficult to conceive, but I believe that is a necessary development that requires an overhaul of current left-wing common sense. If the revolutionary Kautsky — a thinker both dismissed or embraced as a reformist on the Left today — can remind us that there could be another way to go about the struggle for socialism, then all the better.