Poor old Showtime, the pay-cable network, keeps failing where front-runner HBO keeps succeeding: at coming up with weekly shows of high quality and wide appeal. HBO's series generate much more buzz and are produced more inventively than such Showtime duds as, say, "Stargate SG-1" and "Total Recall 2070."

This may be changing. Tonight at 10 Showtime introduces a clever, caustic comedy-drama about the television business that promises to be one of the livelier items of the summer. "Beggars and Choosers," as it's called, is based on a concept by the late Brandon Tartikoff, the genius-boy of TV programmers who, with chairman Grant Tinker, made NBC the No. 1 network in the '80s.

One of the executive producers is Lilly Tartikoff, Brandon's widow, who is a formidable force of nature in her own right.

"Beggars and Choosers" opens with Tartikoff's words on the screen. He's quoted as saying that everyone who works in TV is either a beggar--somebody trying to sell a program to a network--or a chooser--someone empowered to select which shows get on the air. "There are three kinds of choosers," Tartikoff says. "Those who see the glass half full, those who see it as half empty, and those who ask, 'Does it have to be a glass?' "

Television is easy to jeer at but hard to satirize. "Beggars and Choosers" is probably the savviest savage satire of the TV business since Paddy Chayefsky's barnstormer "Network" in 1976. "Beggars and Choosers" is not in Chayefsky's league and not as corrosively entertaining, but it comes close. It's also a touch anachronistic, however, in that broadcast network TV is hardly the center ring of the TV circus that it once was.

Is the central character--Rob Malone, head of programming for LGT, a minor television network--based on Tartikoff? They both went to Yale and they both once aspired to be serious writers, but Malone does not have Tartikoff's self-deprecating wit or mischievous charm. He also seems disillusioned about the competitive nuttiness of network TV, whereas Tartikoff appeared to thrive in it.

Twenty episodes of "Beggars and Choosers" will air this summer, the first 90 minutes long and the rest an hour. In the premiere, written by Peter Lefcourt and directed by Michael Ritchie, we meet Malone, played by Brian Kerwin, and his cunning coven of fellow executives--a pointy-headed, and pointy-nosed, business manager; a closeted gay vice president; and so on. Among the most emblematic is Lori Volpone, flirtatious vice president of program development, played shrewdly by Charlotte Ross.

Volpone follows the basic rules of network executivity that are also operative in Washington's corridors, boardrooms and bathrooms of power: Ally yourself with successes, even if you had nothing to do with them, and distance yourself from failures, even if you had a great deal to do with them.

The LGT network has been wallowing in the ratings cellar, much as UPN does now, but suddenly finds itself with a surprise hit on its hands, a reactionary melodrama called "Mountain Men." Its producer, a kook-ball survivalist firebrand named Kendall Gifford (played by Stuart Margolin, once of "The Rockford Files"), loves to quote Thoreau and has devised a show about men going back to nature. And then maybe back further still.

In one fateful episode, the leader of the Mountain Men preaches a sermon against materialism and urges his fellow tribesmen to throw consumer goods into a bonfire. Although its ratings are very good, when that episode of "Mountain Men" airs, the hit hits the fan. Sponsors are in an uproar over this affront to the gods of conspicuous consumption. The CEO of the network, a kinky old crank named Emory Luddin, flies from New York to Los Angeles to review the troops.

The character of Luddin is wildly overdone and just as wildly overacted (by Bill Morey). But many of the other principal players come off as amusingly, chillingly and tellingly true to life. They scramble madly to advance their own interests and feather their own nests--always on the outlook for bigger and better nests to feather, of course.

Through it all, Malone tries to maintain his integrity, his family (including Isabella Hofmann as wife Cecile, known for her charity work--as Lilly Tartikoff is), his sanity and his faith in the medium, a medium that eats its young when it's not feeding on itself. The soundtrack is scored with melodies from Gilbert and Sullivan just to remind us, perhaps, that this is satire.

Although never quite as scintillating as one wants it to be, "Beggars and Choosers" still makes for a rollicking trip backstage in a business that can be just as bizarre and berserk as is portrayed. Brandon Tartikoff always understood the absurdities of television, and when he got into the movie business (during a brief executive tenure at Paramount), he actually found himself missing them.

This series promises to be a fitting and funny--if inevitably inadequate--memorial to him.

CAPTION: Isabella Hofmann plays the wife of a TV network programming chief in Showtime's new satirical series.

CAPTION: Brian Kerwin and Isabella Hofmann star as a TV network progamming director and his wife in the Showtime series "Beggars and Choosers." Below left, Charlotte Ross is featured as a flirtatious and ambitious network executive.