Rep. Richard A. Gephardt (D-Mo.) has a House-to-House strategy for 1988.

The Missourian has begun talking to his House colleagues about his White House ambitions. He is not yet asking for commitments, but he is telling them he hopes for their support so he can build the nationwide political and fund-raising base he will need to compete for the Democratic nomination for president.

The House strategy is important to Gephardt because, unlike several likely 1988 opponents, he starts with almost no national identity. To establish credibility in the prenomination year of 1987, and collect campaign help and convention votes in 1988, he wants to line up as many as 100 House members, according to informed soruces.

Since the beginning of this year, Gephardt has begun meeting with all Democratic members, ostensibly as a part of his campaign for reelection as House Democratic Caucus chairman. Since he has no announced opponent, he often lets the conversation wander off into 1988.

"In many of the meetings so far, the subject of 1988 has come up, but it's the members who bring it up," said Gephardt press secretary Don Foley, who said there is no systematic campaign to line up 1988 endorsements.

A informal Gephardt group has already emerged in the House. It has a tilt toward youth, moderation and/or the Sun Belt: Reps. Ronnie G. Flippo (D-Ala.), Buddy MacKay (D-Fla.), Chester G. Atkins (D-Mass.), Ron Wyden (D-Ore.), Ed Jenkins (D-Ga.), Marvin Leath (D-Tex.), Charles W. Stenholm (D-Tex.), W.J. (Billy) Tauzin (D-La.), Butler Derrick (D-S.C.), Mike Synar (D-Okla.), Wayne Dowdy (D-Miss.), Richard J. Durbin (D-Ill.), Tony Coelho (D-Calif.), William L. Clay (D-Mo.) and Alan D. Wheat (D-Mo.).

In 1988, with up to 40 percent of the Democratic delegates to be selected on Super Tuesday in early March, the nomination battle will favor the candidate who can organize early and everywhere. Gephardt's strategy is to campaign door-to-door in Iowa and New Hampshire, and become a factor in the mostly southern Super Tuesday states by plugging into the organizations of his colleagues.

The Democratic National Committee adopted rules last week that make 80 percent of House and Senate Democratic members automatic delegates to the 1988 convention, up from 60 percent in 1984.

In 1984, the only candidate who systematically worked the congressional delegates was former vice president Walter F. Mondale, and it paid off. He got 206 convention votes from House and Senate members, to Sen. Gary Hart's 15 and Jesse L. Jackson's 10.

Until last week, Gephardt had the early foraging on Capitol Hill pretty much to himself. But on Tuesday night, Hart got into the act, attending a dinner with six House members elected in 1982 that was put together by Rep. Robert G. Torricelli (D-N.J.). And later this month, Rep. William B. Richardson (D-N.M.), who said he is uncommitted for 1988, is expected to host a dinner to introduce about a dozen younger Democratic members to former Virginia governor Charles S. Robb.