It could be the most tragic what-if in Broadway history: Songwriting team Richard Adler and Jerry Ross wrote exactly two shows together, had two major hits, won two Best Musical Tonys in two consecutive years—and between those awards, Ross died, of lung disease, at age 29.

Already they’d carved a niche with The Pajama Game (1954) and Damn Yankees (1955), both in urban, present-day settings on thoroughly American topics—in snappy contrast to the operetta-like escapism of Rodgers & Hammerstein or Lerner & Loewe. They’re just the sort of shows the 5th Avenue Theatre has long excelled in: with expert casting and pure-hearted affection, restoring any slight luster these and similar Golden Age musicals may have lost over the years. They polished Damn Yankees winningly in 2012, and similarly their Pajama Game, which opened Thursday, will leave you, underneath your exhilaration, aching with regret over what Adler and Ross might have done.

One safe bet is that the two would have developed a surer sense of craftsmanship. Pajama Game, especially, co-developed with book writers George Abbott and Richard Bissell, is structurally a mess. One hit number, “Steam Heat,” is inserted on the weakest pretext; another, “Hernando’s Hideaway,” is not much more plausible; and an entire knife-throwing subplot is just perplexing. The handling of the show’s subject matter, though, is kind of a miracle, combining the personal (specifically, sex) and the political with sophisticated and unprecedented deftness in the story of Sid Sorokin and Babe Williams, who fall in sizzling love despite representing management and labor in a dispute over a wage hike at the Sleep-Tite pajama factory.

So vivid are Billie Wildrick and Josh Davis in the 5th’s production, so thrillingly matched are their Babe and Sid in brass and strength and hot-blooded appetite, that they’ll make you wonder how Adler and Ross got away with this in 1954. (Or, for that matter, with the show’s frank comic treatment of adultery.) Same goes for Kyle Robert Carter as the union president, whose rousing pro-labor speech to open Act 2 would have gotten this production fiercely denounced, if not shut down, by Joe McCarthy. The unmistakable resonance with our current political situation drew audience cheers on Saturday, as it surely will for the rest of the run. Among the supporting cast, splendid without exception, Greg McCormick Allen, as good as it gets when it comes to playing comic male second leads, and Taryn Darr, whose “Steam Heat” completely lives up to its title, have to be mentioned. The 5th Avenue Theatre, 1308 Fifth Ave., 625-1900, 5thavenue.org. $29–$121. Ends March 5.