TV and movie screens won't go blank at the stroke of midnight tonight, but a walkout could take place within a few days if Hollywood writers and producers can't cut a deal.

If the two sides can't reach an agreement by 12:01 a.m. - when the Writers Guild of America's contract expires - several scenarios are possible. 

In one, the union, which has been contacting members about their willingness to help picket and work on phone banks, calls for a strike authorization vote from its 11,500 members. 

If talks are extended past the deadline, the current WGA contract would also be extended, and writers could keep working. 

There's speculation the WGA might extend talks until June 30, when the actors' contracts are set to expire, giving both groups added leverage in negotiations. 

If the writers do strike, the TV industry would be affected first. 

There are about 110 TV shows produced in and around New York City. Talk shows, which have no writers, and network news and public-TV shows, whose writers are bound under a separate guild contract, would not be affected. 

But late-night shows such as The Late Show With David Letterman, Late Night With Conan O'Brien and Saturday Night Live are staffed by some 50 WGA members and could all be derailed. 

An industry source says if there is a strike, Letterman will go into reruns temporarily before negotiating an a waiver with the WGA, so the show can keep going through the strike. 

Movie studios have been on an accelerated production schedule since last year, backlogging films to get them through the fall and winter in the event of a strike. 

Work on such movies as Spider-Man, Kate & Leopold, A Beautiful Mind and Stuart Little 2, currently shooting in New York, will continue as usual - at least until the contracts with the Screen Actors Guild and American Federation of Television and Radio Artists are up for renewal. 

"Films already in production won't be affected by a writers' strike," says Hollywood Reporter film reporter Marla Matzer Rose. "But if the actors also go out on strike, everything shuts down July 1." 

Of course, there's always the chance that harmony will be found at the 11th hour - and writers will bridge their $100 million gap with the Alliance of Motion Picture and Television Producers after nine weeks of negotiations.