House Democrats -- GOP allies?

When Republicans take control of the White House and Senate next month, the House of Representative will remain an island of Democratic resistance -- or will it?

Although the new House will continue to be ruled by Democrats, by a margin of 51 votes, increasing evidence suggests that it may pose less of an obstacle to the conservative policies of the Reagan administration than originally expected.

Without actually changing party control, a change in ideological complexion may make the House a different sort of chamber than it has been during many of its preceding 24 years as a Democratic stronghold.

An ideological analysis of the incoming House by the National Committee for an Effective Congress, a group that aids chiefly liberal Democratic candidates, detests an outright conservative majority -- 51 percent of its members classified as conservatives vs. 49 percent as liberals and moderates.

The new House GOP leader, Rep. Robert H. Michel of Illinois, openly wooing support among conservative Democrats, agrees.

"There is a good opportunity for us to carry the day on some philosophical issues," he told reporters at breakfast Dec. 15.

The winds of change, which began to blow when Republicans swept 33 House seats from the Democrats in the November election, have gathered force in a series of postelection developments. Among them:

* Committee makeup. A conservative Democrat known for his coalition-building with Republicans, Rep. James R. Jones of Oklahoma, was elected chairman of the crucial Budget Committee last week over liberal Rep. David R. Obey of Wisconsin.

The equally important Ways and Means Committee, which writes the nation's tax laws, is about to lose its chairman and three other senior Demoractic liberals via election defeats and retirements.

"Ways and Means has no strong liberal left at the top, after having been primarily a liberal committee since the political demise of [longtime chairman] Wilbur Mills," says ranking Republican member Barber B. Conable Jr. of New York, adding that the committee has "very few junior members with liberal inclinations , either."

* Democratic leadership changes. The newest addition to the party's inner circle, as chief deputy majority whip, is a moderate Southerner, Rep. William V. Alexander Jr. of Arkansas. His liberal rating by the Americans for Democratic Action is only about one-half that of his successor, Rep. Dan Rostenkowski of Illinois, new chairman of Ways and Means.

Three out-and-out conservatives from the South were appointed to the weighty Democratic Policy and Steering Committee. Another Southerner, Gillis W. Long of Louisiana, was elected chairman of the party caucus.

The new Democratic team is sending the incoming Republicans conspicuously conciliatory signals. "We're Americans first and Democrats second," says majority leader Jim Wright of Texas. "We will have our own ideas, but we want to go ahead and work with the President."

* New conservative Democratic group. Some 34 conservative Democratic, who potentially wield the balance of power in the new house, have organized themselves as a Democratic Conservative Forum to bargain for a larger role in the majority party.