What if Letterman had succeeded Carson?

Marvel Comics used to publish “What If…?,” a title that explored alternative universes triggered by a slight tinkering with past events.

Journalists seldom indulge in such flights of fancy. Still, with Jay Leno preparing to face off against David Letterman in latenight — renewing a battle interrupted by Leno’s ill-fated move to primetime and following an amusing Super Bowl rapprochement — it got me wondering: What if NBC had given “The Tonight Show” to Letterman in the first place, as he always wanted?

Unlike some scenarios — such as the first issue of “What If?” in which Spider-Man joined the Fantastic Four — this one isn’t particularly far-fetched. NBC execs wrestled with the Leno-Letterman choice once it became known the latter wouldn’t settle for staying in the “Late Night” slot, and there were high-ranking allies within the network who favored installing the gap-toothed host as Johnny Carson’s successor.

Had that happened, Leno almost surely would have gone elsewhere — probably CBS, which was circling like a hungry shark. Like Letterman, Leno would have started from scratch, taking over a timeslot then occupied by cheesy latenight dramas under the “Crimetime After Primetime” banner.

In terms of tone and style, though, Leno’s comedic sensibility would have actually provided a more complementary fit with CBS’ heartland audience. And Letterman would have slid into the “Tonight” seat with the blessing of Carson (who preferred him) and a soon-to-arrive

primetime boost from shows like “Frasier,” “Friends” and “ER,” whose hipper “Must-See TV” audience would have been more compatible with his sardonic brand of humor.

Both hosts, in other words, still would have been successful — perhaps more so — while avoiding much of the acrimony associated with Letterman’s leap to CBS. With Leno less apt to play the aggrieved party, among the losers in this revised chain of events would have been the New York Times’ Bill Carter, who would have found it difficult selling a book (much less an HBO movie adaptation) that would have been far less zesty.

A more interesting question is whether Conan O’Brien — the then-unknown NBC tapped to replace Letterman on “Late Night” — would have ever landed that gig had Letterman stuck at NBC.

Based on the available evidence, it appears unlikely.

Letterman, after all, is a fountain of neuroses, and the latenight succession battle certainly did nothing to quell them. When Letterman launched a CBS companion program in the mid-’90s, “The Late Late Show,” he turned to Tom Snyder as its first host.

Although he lauded Snyder as a “talented broadcaster,” it was obvious he chose him in part because Snyder’s low-key interview format represented no threat to him. Given that, it’s difficult to imagine Letterman sitting idly by while NBC tapped a young host with a similar comedic sensibility — even one as unknown as O’Brien was back in 1992.

In other words, Coco would have been a no-go from the get-go.

The constant in both universes is that Letterman and Leno’s fates were inextricably entwined, because so few performers — either due to talent, temperament or work ethic — are suited to fronting a nightly comedy program. The two had plenty of stand-up contemporaries who also cut their teeth on “The Tonight Show” and are seldom seen these days.

It’s hard to envision an accomplished malcontent like Letterman being completely satisfied even had he been anointed the heir to Carson, whose shadow looms so large over latenight’s clown princes as to flummox Freudian analysis. (When Letterman signed a “Late Night” contract extension with NBC during Brandon Tartikoff’s era, the host issued a statement that said, “I’m not sure how, but I’m convinced I’ve been screwed.”)

Still, had Letterman emerged the victor at NBC, it’s possible both hosts would not only have been happier (or at least less miserable) but more popular.

And while there’s usually nothing to be gained from agonizing over “what if…,” after the bad blood and taunts that spilled out over NBC’s recent latenight mess, it’s clear that for Letterman the old scars have never entirely healed.

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