Washington's zaniest form of political warfare, in which blocked presidential appointments are used as bargaining chips to influence arms control and other areas of foreign policy, has broken out once again in the Senate in perhaps the most bizarre flare-up so far this year.

On one side, at the urging of the White House, Senate Majority Leader Howard H. Baker Jr. (R-Tenn.) served notice Tuesday he will finally call up for confirmation votes several presidential nominees whose appointments have long been blocked by ultraconservatives. That carries the risk of a filibuster in this lame-duck session of Congress.

The ultraconservatives, moreover, led by Sen. Jesse Helms (R-N.C.), have cautioned it could also cost the administration needed support for its MX missile.

That implicit warning was delivered Tuesday at a briefing on the MX plan by Thomas C. Reed, a special assistant to the president, and Air Force Brig. Gen. Gordon Fornell, for the Senate Steering Committee, an unofficial group of conservatives headed by Helms and Sen. Orrin G. Hatch (R-Utah).

Hatch is reported to have told Reed it would be easier for the conservatives to support the administration on its new MX "Dense Pack" basing plan if there were different officials in positions of responsibility for shaping U.S. policy on arms control negotiations with the Soviet Union.

The current prime targets of the Steering Committee are Richard R. Burt, awaiting confirmation since September as assistant secretary of state for European affairs, and Robert Grey, whose confirmation as deputy director of the Arms Control and Disarmament Agency (ACDA) has been blocked since March. Both are serving in those posts in acting capacities.

According to several sources, Helms told Reed at the end of the MX briefing that if the administration attempts to bring up MX and also push through the disputed nominations, there will be "blood on the floor" of the Senate and "I'm going to be as angry as a pregnant cobra."

Hatch reportedly told Reed that the Steering Committee, which has 16 members, was acting as "a corporate body" in insisting on officials who will take a tougher position on verification of any arms control accord with the Soviet Union. Sens. Strom Thurmond (R-S.C.) and Steve Symms (R-Idaho) were said to have also registered opposition to the disputed nominees.

None of the senators would comment for publication on the threats and feints at the meeting. One Senate aide said the senators were blunt in linking support for MX to withdrawal of the disputed nominees. Others said it was more subtle than that.

A member of Helms' staff said there was no talk of an outright "quid pro quo." But this aide said it was made clear that if "the administration wants conservatives to carry water on this [MX] issue," the administration in turn should be "accommodating on other issues."

Helms and his fellow conservatives favor putting maximum pressure of all kinds on the Soviet Union, and many administration officials therefore look on their threats to vote down the MX as a bluff. But other officials say they are apprehensive about any floor debate with the ultraconservatives on arms control, which could "turn into an embarrassing circus" over who is more loyal to the anti-communist commitments by Reagan in his presidential campaign.

The blocked nominees are pawns in this dispute, many participants on both sides concede in private. Secretary of State George P. Shultz on Monday met with Baker to reinforce renewed White House requests for action on the stalled appointments.

Burt is supposed to accompany Shultz on his scheduled Monday trip to Western Europe for talks that will include a meeting of foreign ministers of the North Atlantic Treaty Organization in Brussels.

The Burt nomination was approved by the Senate Foreign Relations Committee in September, over Helms' opposition. Helms charged that Burt as a New York Times reporter in 1979 damaged national security by reporting on satellite monitoring facilities lost in the Iranian revolution. Other committee members disagreed that this made Burt unacceptable for an official post.

Opposition to Burt subsequently broadened to nuclear arms control issues, on which he is alleged to be insufficiently hawkish, and alleged "indiscretions," which he denies. He has declined any public comment.

In the nine-month-long dispute over Grey's nomination, Helms and his associates originally set out to block confirmation not only of Grey but also of another senior official in ACDA, Norman Terrell.

Baker last July tried to mediate that dispute with Eugene V. Rostow, director of the arms control agency, and Helms offered to withdraw the opposition to Grey if Terrell were moved out ACDA. Helms' associates now say that offer is dead.

On Monday, nevertheless, Terrell was indeed moved out; he was appointed an associate administrator of the National Aeronautics and Space Administration, a senior post that requires no Senate confirmation.

Rostow, who is recuperating in Connecticut from a hip operation, said on Tuesday that he has completed his part of "the deal" and expects Helms to fulfill his part. "I have no positive evidence that Helms will repudiate his deal," Rostow said, "and I find it very hard to believe that Senator Helms will welsh."

Meanwhile, senators on the other side of the ideological divide, Edward M. Kennedy (D-Mass.) and Joseph R. Biden Jr. (D-Del.), have turned Helms' tactics against him. They put senatorial holds on the confirmation of appointees from ultraconservative ranks, especially that of Richard McCormack, now serving as assistant secretary of state for economic and business affairs.

McCormack is a former Helms aide. The holds on him are still in force, as are the Steering Committee's holds on Grey and Burt. The questions now are what the White House will do and when Baker will try to bring all three nominations -- of Burt, Grey and McCormack -- to a vote.

Beyond personalities, the effort to harden U.S. policy toward the Soviet Union already has had substantive impact, many insiders say, although administration officials deny this. Currently before the White House are proposals for stiffening U.S. terms for ratifying two sidetracked treaties with the Soviet Union, the Threshold Test Ban Treaty of 1974, and the Peaceful Nuclear Explosions Treaty, signed in 1976.

The current proposals would require the Soviet Union to accept terms for on-site inspection of underground tests that go far beyond the requirements already negotiated. According to several sources, the new terms were expressly designed to be responsive to criticism raised by ultraconservatives in the executive branch and in Congress.