Montgomery County Congressman Michael D. Barnes is just a guy who can't say no.

Barnes, whose name does not appear on the ballot in next Tuesday's election because he has no primary opponent, has nonetheless found himself in the middle of a bitter feud between rival Democratic County Council slates, with each side clamoring for a favorable Barnes quote or a Barnes photograph to run with their ads.

"Each time I said something nice about one side, the other side escalated the degree of niceness," Barnes explained.

Barnes said he tried to make it clear from the beginning that he wasn't endorsing any of the council candidates. But he agreed to say nice things about Democrats, even if they were running against each other.

"It's a case of trying to be friendly to friends," Barnes said. "Unfortunately it's ended up like this."

Yesterday, Barnes agreed to make one last statement on the whole mess "by way of trying to extricate myself." Council President Neal Potter, heading a council slate called United Democrats, trooped up to Barnes' Capitol Hill office armed with a tape recorder to get Barnes to say nice things about the United Democrats slate for a radio spot.

The radio spot, which will begin airing today on WTOP radio, begins with Potter announcing "an urgent message" to voters. His opponents "are so desperate for approval they've distorted Congressman Barnes' polite remarks," Potter intones. Then Barnes says, "The only county government candidate I've endorsed is [county executive] Charlie Gilchrist. I know and admire people on all the Democratic council slates and I regret that anyone may have been misled into be- lieving I've endorsed any slate in particular."

Potter was trying to negate the impact of another Barnes quotation, favorable to the opposing Merit Team slate headed by council member David L. Scull. The quote is being used in a Merit Team radio spot and in a newspaper advertisement.

The United Democrats accused the Merit Team of dirty tricks, saying the Scull radio spot made Barnes' favorable remarks sound like an endorsement. Scull has retaped the spot, but Potter's team feels the damage has been done, especially since the newspaper ad contained a photograph of Barnes.

Merit Team candidate William Hanna, the former Rockville mayor, said his team accepted Barnes' offer for a quote only after the congressman told him he had given a similiar statement to his opponent, United Democrats' candidate Ruth Spector.

Incumbent council member Spector said she approached Barnes last month for a quotation to use in her commercials, which begin today.

Hanna said yesterday that as a result of the uproar, he has scrapped his commercial containing the Barnes quotation.

Barnes is not the only politician caught in the squeeze of rival candidates scrambling for favorable words to headline their literature.

Former Republican congressman Newton I. Steers, who is running for lieutenant governor, endorsed his former campaign aide Del. Luiz R. Simmons for county executive. Simmons has been using a Steers' quotation in his literature.

But when Simmons' principal primary challenger, banker Joseph McGrath, asked Steers for a similar quotation, he got one too.

Steers insists he is still endorsing Simmons, despite the favorable words for McGrath. "It doesn't say I like McGrath better than Simmons," Steers said.