The Senate defied the White House on arms control again yesterday by signaling support for legislation to force the administration to resume compliance with the unratified 1979 SALT II treaty with the Soviet Union.

But approval of the proposal was blocked by Republicans until Senate leaders, after hours of negotiations lasting into the night, agreed on a procedure for final votes today on the SALT II issue and then passage of the long-delayed defense authorization for fiscal 1988.

Democrats abandoned their efforts to amend the defense bill to impose war-powers restrictions on the administration's tanker-escort operation in the Persian Gulf by requiring congressional approval for long-term continuation of the operation.

Under the leaders' agreement, the war-powers issue can come up next week as separate legislation without any assurance of a final vote, exposing it to indefinite delay from a GOP filibuster.

Earlier yesterday, an attempt by Democrats to hasten action on the Persian Gulf provisions fizzled when the Senate voted, 54 to 45, to shut off debate, falling six votes short of the 60 necessary for cloture but indicating that a "clear majority of the Senate" favored the gulf constraints, as Majority Leader Robert C. Byrd (D-W.Va.) put it. A subsequent attempt by Republicans to invoke cloture in a way that would strip the defense bill of the Persian Gulf restrictions failed.

The Democratic-controlled Senate's support for the SALT II compliance requirements came on a 55-to-44 vote against tabling, and effectively killing, a proposal from Sen. Dale Bumpers (D-Ark.) to require the administration to resume adherence to treaty limits for various categories of nuclear weapons.

The margin was larger than expected despite a concerted drive by SALT II foes, who used news of two new Soviet ballistic missile tests, including one with a target area only 500 miles from Hawaii, as a focal point of their contention that the Soviets were willfully violating the treaty to gain an advantage over the United States.

The Soviet tests continued to send off sparks even after the vote. Sen. John W. Warner (R-Va.) charged that the Senate was responding to the Soviet missile firing with a "thank-you note," prompting a warning from Byrd against impugning the "patriotism or honesty" of senators who supported the SALT II constraints.

While the vote indicated the Senate will include the provisions in its final version of the defense authorization bill, it does not mean the SALT II requirements will become law.

President Reagan has vowed to veto the bill for other reasons, and Senate votes on most key issues in the bill indicate that Congress could not muster the two-thirds margin necessary to override a veto.

While the House has consistently approved SALT II restrictions, they have been rejected in previous years by the Senate, which was under Republican control from 1981 to 1986.

The House has included language similar to the Bumpers proposal in its version of the defense bill for fiscal 1988.

Although the SALT II treaty was never ratified by the Senate, it was observed by the United States until late last year when Reagan abandoned compliance and broke the weapons limits by equipping and deploying the 131st bomber with nuclear-tipped cruise missiles.

The administration has charged the Soviets with violating the treaty and opposed legislation to force U.S. compliance with it.

Yesterday's action was the second major rebuff to the administration on arms control by the Senate, which last month voted, 58 to 38, to curb testing and development of Reagan's Strategic Defense Initiative (SDI) that goes beyond a narrow interpretation of the 1972 Antiballistic Missile (ABM) Treaty.

In yesterday's vote, eight Republican moderates joined most Democrats in indicating support for the SALT II provisions. Seven Democrats, mostly Southern conservatives including Armed Services Committee Chairman Sam Nunn (D-Ga.), joined most Republicans in opposing them.

Maryland's Democratic senators supported the restrictions; Virginia's Republicans opposed them.

Bumpers' proposal requires adherence to treaty limits for multiple-warhead ballistic missiles and bombers unless the president certifies that the Soviets are violating them or that he is unable to certify their noncompliance, based on available intelligence assessments.