WASHINGTON — WASHINGTON -- In the latest sign of the Democrats' eroding base, a conservative House member joined the Republican Party yesterday, becoming the third congressional Democrat to abandon the party since the GOP took control of Congress last year.
The defection of Rep. Nathan Deal of Georgia, part of a vanishing breed of conservative Democrats in the House, strengthens the Republicans' hold on the South -- a one-time Democratic stronghold that now has a GOP majority in the House.
The Deal departure further narrows the philosophical base of the party, which is becoming increasingly identified with liberal causes.
It is also a bad omen for Democrats with any hopes for retaking control of the House in 1996. The Republican margin over Democrats in the House is now 231-203, with one independent.
"What a disaster for the Democrats," said Stuart Rothenberg, a congressional analyst, who said that Mr. Deal's party switch could trigger others. "This just adds to the problems they have in the region."
Mr. Deal, 52, was one of only four Democrats in the 11-member Georgia delegation, and the only white member.
As recently as last year, Georgia had a seven-member Democratic majority: four whites and three blacks.
The most recent congressional reapportionment, in which many districts in South were redesigned to give black candidates the strongest chances, have also weakened election prospects for Southern white Democrats, who lost many of their black constituents in the process.
Two conservative Democratic senators -- Richard C. Shelby of Alabama and Ben Nighthorse Campbell of Colorado -- have also switched parties since Republicans gained control of Congress last fall.
Two more Southern Democrats, Howell Heflin of Alabama and J. Bennett Johnston of Louisiana, have chosen to retire from the Senate rather than seek re-election in 1996.
Those moves have made it almost impossible for the Democrats to retake control of the Senate, where they are outnumbered 54-46.
"I think this is part of a very deep political realignment that is almost to the point where white conservative Democrats can't get elected in the Deep South," said Merle Black, a professor of political science at Emory University in Atlanta. "The base has just collapsed beneath them."
Mr. Deal was one of two dozen or more mostly Southern conservative Democratic House members who bucked their party leadership to support most of the Republican "Contract with America."
The congressman said yesterday that his decision to change parties was "based on principle, not politics."
"During the last 100 days, I have observed my party at the national level simply not be willing to admit that they are out of touch with mainstream America," Mr. Deal told reporters in his north Georgia district. "I think it is important that at some point you get away from the schizophrenia that I have had to deal with."
House Democratic leaders, who had worked with Mr. Deal to craft a Democratic substitute for the Republican welfare reform bill last month, responded bitterly yesterday.
"For the 204 Democrats who worked hard to find a compromise and ultimately support Representative Deal's welfare reform alternative, I can only say that they are surprised and disappointed as I am at his decision," said House Democratic Leader Richard A. Gephardt of Missouri.
But only the timing of Mr. Deal's reversal came as a surprise. He had been courted by the Republicans since the fall, when he was included on a list of possible recruits if the GOP had fallen a few votes short of winning a House majority.
But he told the Atlanta Journal and Constitution before the election that he didn't think it would be "honest" to "run with one party label and then, after the election, change parties."
Mr. Deal made similar comments to a Georgia radio station three months ago. "If I choose to switch during the term, I think the honest thing to do is to resign and have a special election," he said.
Rep. Martin Frost of Texas, chairman of the House Democratic Congressional Campaign committee, called on Mr. Deal to "honor his word, step down and give the people of north Georgia an opportunity to choose their representative with all of the information on the table."
Mr. Deal was not available to respond to Mr. Frost's challenge.
Rep. Bill Paxon, the New York Republican who heads the Republican Congressional Campaign Committee, said he believes that Mr. Deal's constituents will be more than sympathetic to his decision to leave a party that "is leaning much more to the left, even [more] than it was when Bill Clinton was running for president."