The Democrats call it a $6 million preemptive smear campaign. The chairman of the Republican Congressional Campaign Committee, Rep. Guy Vander Jagt (Mich.), calls it an "incumbent accountability program."

Whatever it is, the super-early spring offensive has gotten all tangled up with President Reagan's big bipartisan drive for the MX missile, and he has ordered it stopped. Vander Jagt, however, says it will go on.

The Democrats say the president cannot call for bipartisanship on tough issues like the MX and at the same time sign letters asking for money so Vander Jagt can go out and bash them.

Vander Jagt says he has no hit list for 1986 -- that, he says, is a "figment of the imagination" of his opposite number, Rep. Tony Coelho (Calif.), head of the Democratic Congressional Campaign Committee. The news briefing he gave on Feb. 27 was "misinterpreted," Vander Jagt says, adding that he has not "targeted" some 20 or 30 Democrats from districts where the president did well last November.

The Vander Jagt plan calls for an expenditure of some $6 million 18 months before the bell rings in the 1986 campaign and well before most Republican opponents are chosen. The idea is that the Democrats will go into the ring so softened up by a heavy barrage of negative television and radio ads and direct mail that they will be candidates for a quick knockout.

Vander Jagt says his effort will be a "nonhysterical, factual and responsible effort to call to account any Democratic incumbent who is trying to wrap himself in the mantle of Ronald Reagan."

The president got an earful about the Vander Jagt initiative from three of its intended victims, who had come to the White House to be lobbied about the MX.

First in at 11 a.m. was Rep. Marilyn Lloyd (D-Tenn.), who has always voted for the MX but has decided to be undecided this time because of budgetary considerations. When the president began a little tribute to the virtues of the "Peacekeeper," as he likes to call the MX, she told him that she and her fellow conservative Democrats were "appalled" by his party's efforts to unseat them.

The president protested that he didn't have anything to do with it, was not aware of it. He said it was a decision made by the Congressional Committee. The congresswoman pointed out that in the last campaign two letters on behalf of her opponent went out over his signature.

At 11:30 the president took more flak, this time from a genuine Boll Weevil, Rep. Charles W. Stenholm (D-Tex.). He told the president that "the kind of political activity being engaged in by Vander Jagt doesn't make bipartisanship on the MX as easy as it should be." He said the president seemed "genuinely surprised."

At 1:30, Rep. Stephen L. Neal (D-N.C.) went in with three other pro-MX Democrats. When the president began to make his pitch, Neal asked him point-blank: "How can you expect bipartisanship when you are raising money over your signature for this Vander Jagt effort?"

"I want it stopped," Neal says he told the president. "I don't want my name taken off any list; I want the whole thing stopped."

The president, according to Neal, said he didn't know anything about it, so Neal showed him a list out of Vander Jagt's committee, and the president said he thought "this kind of effort would be counterproductive."

"I told him I knew he would stop it," Neal says, "and I believe he will."

Apparently, the president tried. At a Monday breakfast meeting with reporters, he said, he had "expressed my desire that we stop this." He had his congressional liaison, Max Friedersdorf, order Vander Jagt to cease and desist.

But Vander Jagt says it was White House political director Edward F. Rollins who called him and said "the president can in no way be part of that program."

Vander Jagt understands that the president will have to be kept clear of any dirty pool, but he expects him to sign more fund-raising letters for the program.

"If the president called me in and said 'please, please, please stop it,' I would, but I think he realizes that that would be inappropriate. Nothing I have heard from anyone has done anything to change my intention."

Democrats find being targeted a harrowing experience. For instance, Rep. Edward F. Feighan (D-Ohio), who was targeted last time, saw himself presented in a Republican TV commercial as a puppet labeled "Congressman Fagin -- he's got his fingers in your pocket" -- until Jewish voters protested and the commerical was yanked.

Coelho is skeptical about the vetoing of the program. "We will see if he follows through. I am pleased that the president agrees with us about this. I recognize that after the MX vote is behind him, he may decide that he will go ahead with it."