Has the bleeding finally stopped on "Letterman"?

CBS's "Late Show With David Letterman" may be off the critical list, thanks in large measure to the network's improved ratings fortunes in the 10 p.m. hour on Monday, Tuesday, Wednesday and Friday.

While his show was sliding down the ratings slope, Letterman groused that the network's anemic performance in the last hour of prime time was to blame. That's changed now. CBS has increased its viewership at 10 every weeknight except Thursday, where it's flat compared with last season. In the four-week-old 1999-2000 TV season, the network has seen improvements at 10 p.m. that range from 41 percent (Monday's "Family Law" this season compared with last season's "L.A. Doctors") down to 6 percent (Wednesday's movie vs. "Chicago Hope").

Letterman's theory seems to have been correct. His late-night talk show is still trailing Jay Leno's on NBC by a fair amount, but his lag this season is the smallest since 1996-97. "Late Show," with 4 million viewers, is now running about 1.7 million shy of "The Tonight Show." Last year at the same time, Letterman had 3.4 million viewers and Leno 5.9 million.

"After all the years of people knowing that there are remote controls, that old-fashioned network programming flow still does exist for a lot of people," CBS Senior VP Mitch Semel said of Letterman's better numbers.

Has NBC told celebrity liberal Martin Sheen that his series "The West Wing" has the highest concentration of young Republican viewers of any new series? Yesterday the network unveiled a list showing that the White House drama series, in which Sheen plays an Armani-suited president, has attracted more adults ages 18-49 with a household income of at least $75,000 than any other of this season's new shows.

As a service, The TV Column is listing the top five programs, so you'll be sure to know which show names to drop to impress your more affluent 18-to-49-year-old acquaintances next time you run into them at the Range Rover dealership or sipping lattes at Starbucks. See if any surprise you:

No. 2: ABC's in-our-forties-and-divorced-but- dating drama, "Once and Again."

No. 3: NBC's misunderstood-'80s-high-school- geeks drama, "Freaks and Geeks."

No. 4: NBC's misunderstood-young-geek- literary-gent-stuck-with-a-Stephen Kingesque- horror-writer sitcom, "Stark Raving Mad."

And . . .

No. 5: NBC's weekly hour of sex crimes, "Law & Order: Special Victims Unit."

You're wondering, perhaps, how The TV Column knows that Martin Sheen sports Armani suits as president on "The West Wing." We have it on the authority of Project Abolition--a consortium of groups advocating immediate reductions in nuclear arms.

Yesterday in Washington the organization unveiled a 60-second commercial espousing the cause. It stars Sheen, who's seen strolling along the steps of the Jefferson Memorial, telling viewers that "politicians are in denial about nuclear weapons." And, according to Project Abolition, he's wearing "a dark blue Armani suit on loan from the set of 'The West Wing' to be worn when he plays the president."

The ad starts running next week and will be placed mostly on cable news programs, because broadcast TV is so expensive, a Project Abolition rep says. Which will be a relief to NBC. Imagine its sartorial embarrassment had Sheen the Armani-suited anti-nuke activist shown up during a commercial break in an episode of "The West Wing" in which Sheen the president was sporting the exact same suit.

And while we're at it, how does NBC feel about having Sheen wearing one of "West Wing's" suits in an anti-nuke ad? NBC is, after all, owned by GE, which is in the nuclear power business. We called NBC to ask; it had no comment. But one industry insider points out that NBC doesn't actually own the suit, it's just renting it from Warner Bros., which produces the show.

Not only is the NBC series "Homicide: Life on the Street" coming back from the dead for a "Homicide: The Movie" presentation this season, but actors Jon Polito and Daniel Baldwin, whose characters were killed off in the course of the series's seven seasons, will resurrect their old characters.

Both Detective Steve Crosetti, played by Polito, and Detective Beau Felton, played by Baldwin, were deader than doornails by the time the series signed off last season. In a 1994 episode, Crosetti was found dead in the water after having been missing for three days. Detective Stanley Bolander, portrayed by Ned Beatty, concluded that the death was a suicide.

Felton was killed while working undercover to crack an auto theft ring in a 1997 episode. Baldwin actually had left the Baltimore-based cop show at the end of the third season in 1995 to pursue a movie career.

NBC's not talking about how their resurrections come about. The network will say only that the premise for the movie revolves around the shooting of one of the department's own, which reunites the detectives to search for the perpetrator, and that the movie will "answer unresolved questions from the show's final season."

CAPTION: David Letterman last week with guest Farrah Fawcett: Is "Late Show" on the ratings rebound?