NEW YORK — Strike or no strike, Carson Daly's back at work on "Last Call." But what does this mean?

Is it the first crack in the dam that has kept late-night talk shows in repeat mode since November 5 in support of the writers walkout?

Is Daly the canary in the mine shaft, about to take pent-up heat as the first talk-show host to cross the picket line?

Is this an effort to save jobs at a show that, while in strike-imposed hiatus, was threatened with layoffs by NBC?

Is Daly thumbing his nose at the strike by inviting volunteers to record jokes on his voicemail for playback on the show? ("At some point my first week on air I will be mentioning the devastating writers strike and saying .... `a TON of my friends and family have been calling me, leaving messages, offering their help with jokes because they know that I don't have any writers working....,"' Carson explains in an e-mail leaked to TheSmokingGun.com.)

Whatever the case, it's a cinch the half-dozen other late-night shows will watch with interest, and perhaps longing, as "Last Call" returns Monday night. While none so far has announced plans to follow suit and tape new shows without their staff writers, pressure will surely continue to mount as the strike enters its fifth week.

One pressure point: ABC News' "Nightline" has been closing the ratings gap with reruns of the "Tonight Show with Jay Leno" on NBC and CBS' "Late Show with David Letterman," which was beat by "Nightline" in total viewers the week of November 12.

"Last Call," which airs weeknights at 1.35 a.m., is primarily an interview show with musical guests. Also part of the formula: a monologue or other comedy bit (the show normally has three staff writers).

The Writers Guild of America, which is striking over payment for work distributed over the web, blasted "Daly's call for non-Guild writers to provide him with jokes." (NBC declined to comment on Daly's "joke hotline.")

Issued late Tuesday, the statement also complained that Daly "is not a writer and not a member of the WGA, unlike other late-night hosts ... who have all resisted network pressure and honoured our writers' picket lines."

But there is precedent for late-night hosts to reclaim their duties during a strike — even another host named Carson.

The 22-week writers strike that began March 7, 1988, plunged "The Tonight Show" into reruns for two months. Its restless host, Johnny Carson, returned on May 11. As a nonmember of the Writers Guild, he was free to write his own monologue, and did.

"I just could not stay away any longer from all things that are going on in the country," he told his audience, then joked that the picket line he crossed was "weird": "The writers are out there holding up these signs, and there's nothing on them."

By the end of May, Carson got welcome assistance. A special agreement with the Writers Guild brought the show's dozen writers back to work.

David Letterman wasn't so lucky. Months of "Late Night" reruns came to an end on June 28 with his return. But he, too, was deprived of his writers — and as a Writers Guild member, was barred from writing material himself.

Until the strike was settled in early August, "Late Night" baldly substituted comedy with freewheeling filler. For instance, this was the strike equivalent of a gag: "Lady of Spain" played on the accordion by the show's associate director, night after night.

"Fifty-five minutes, ladies and gentlemen, 55 minutes to go!" Letterman would announce early in his monologue. "That's all we're really trying to accomplish, is to eat up valuable network time."

Of course, Letterman did weigh in on the strike, ad-libbing such terms as "money-grubbing scum" when referring to management.

What sort of colorful strike-related labels might Letterman be voicing were he back on camera tonight?

Bill Scheft, a longtime writer for Letterman, suggests the veteran host would be no less outspoken now than in 1988 — and that he would be an effective mouthpiece on behalf of the union.

"Dave Letterman on the air, without writers, angry, is the best ally that writers can have," Scheft says. "He's angry about this and he supports us."

Letterman's behind-the-scenes support has extended to paying his nonwriting staff, as well as that of "Late Late Show with Craig Ferguson" (which Letterman also produces), at least until the end of the year. NBC's agreement not to lay off "Tonight" and "Late Night" staffers lasts only through this week, with any further employment yet to be decided, according to an NBC spokesperson.

So maybe Daly was trying to safeguard the jobs of his staffers, which he has. Meanwhile, back on the air, he's unlikely to bad-mouth his network bosses. At "Last Call," the watchword is clearly "the show must go on."