Kenny Gamble and Leon Huff understood early on how plans and aspirations could be vulnerable to economics. Meeting by chance in an elevator — as the only black songwriters in Philadelphia’s Schubert Building — the songwriting partners spent the 1960s hustling for hits, repeatedly thwarted by bad deals and worse luck.

When the pair, along with Jamaican-born producer and arranger Thom Bell, struck a deal in 1971 with Columbia Records, naming their imprint Philadelphia International Records was an audacious statement of intent. But their ambition was soon vindicated with musical acts from Philly blazing a trail in chiffon and sequins across television sets on both sides of the Atlantic. As the economic shocks of that decade began to tighten their grip, though, this aspirational music entered into a unique dialogue with the harsh realities of American life — particularly black American life — in the 1970s.

If their first hit — the O’Jays’ tetchy, paranoid 1972 single “Back Stabbers” — hinted at more adult themes than their Motown contemporaries, then the following year’s smash “Year of Decision” by the Three Degrees proved that something remarkable was going on over in the City of Brotherly Love. Taking advantage of developments in FM radio quality, this was a black creativity broad enough to encompass both disco and Rachmaninov. Get past the orgasmic strings, though, and you’ll hear a plea for togetherness, coupled with sharp warnings about the alternative. “People have died to set you free,” cautions vocalist Fayette Pinkney. Whether by accident or by design — it’s unclear — the single shared a name with a Ronald Reagan speech cut into flexi disc and widely distributed on the campaign trail in California a few years prior.