A few months ago, our reporting team spotlighted how Joe Biden’s campaign was suggesting that if Donald Trump is defeated, a new Democratic administration may not even try to fulfill its campaign promises because of deficit concerns. When our story went viral, Biden’s campaign frantically — and rightly — backtracked, which was a huge win for accountability journalism.

At the final 2020 presidential debate last night, that success culminated in one of the most important moments in the entire campaign.

During a discussion about the budget, Biden brushed off his old deficit hawk buddies, outright rejected GOP talking points, and instead made the point that the federal government must spend what it takes to rescue cities and states.

“Every single state out there finds themselves in trouble — they’re gonna start laying off, whether they are red or blue, cops, firefighters, first responders, teachers, because they have to balance their budget,” Biden said. “The founders were smart. They allowed the federal government to deficit spend to compensate for the United States of America.”

Overall, the debate was demoralizing and depressing, but this moment wasn’t. It was a moment that won’t get a ton of attention from a media obsessed with frivolity, but it wasn’t some small matter. It was everything. If a new administration accepts deficit concern trolling and the Beltway’s austerity frame, then it is doomed to fail. If a new administration rejects that frame, then the possibility of real change remains alive.

It is hard to overstate how big a shift this is for Biden. He was the guy who spent decades touting his work with Republicans trying to cut programs like Social Security in the name of budget austerity. Now he’s expounding on the need for countercyclical deficit spending. To use a Biden-ism, that’s a BFD.

Biden’s rhetorical change is not only good politics, it is sane policy. With the economy in crisis, and with states unable to deficit spend, the federal government must be the demand-side spender of last resort. And it’s not like there aren’t priorities that require big funding — investments in jobless benefits, infrastructure projects, and climate change mitigation will boost the economy and are desperately needed, for obvious reasons.

Biden’s declaration will be particularly important in the coming months, because we already know that if he wins, Republicans will suddenly start pretending to care about deficits, right after they themselves have been deficit spending at a record pace.

If you think that won’t happen, see this passage buried in a recent Bloomberg News report:

A GOP strategist who has been consulting with Senate campaigns said Republicans have been carefully laying the groundwork to restrain a Biden administration on federal spending and the budget deficit by talking up concerns about the price tag for another round of virus relief. The thinking, the strategist said, is that it would be very hard politically to agree on spending trillions more now and then in January suddenly embrace fiscal restraint.

This is part of Republicans’ predictable playbook. They have no actual principles other than trying to obtain power for themselves and deny it to their opponents, everyone in the country be damned.

The question is whether or not Biden musters the fortitude to stick by the position he expressed tonight. It is an open question, because over the course of the campaign, he has periodically cited deficit concerns to justify his opposition to major initiatives such as Medicare for All — an opposition that he gratuitously reiterated in one of the debate’s many low points.

His statement supporting necessary deficit spending at the debate was a complete rejection of that entire deficit hawk rationale.

If he wins, it will be up to congressional Democrats to hold him to his new, better position. They will have to force him to support major investments and oppose the kind of destructive austerity ideology that previously defined Biden’s own record and that would further crater the economy.