Democratic leaders yesterday pulled off the Senate floor a troublesome resolution saying the president should not terminate mutual defense treaties without Senate approval.

Sen. Harry F. Byrd Jr. (Ind.-Va.), had sponsored the sense-of-the-Senate resolution after President Carter announced he was terminating the U.S. defense treaty with Taiwan as part of the agreement to establish relations with mainland China. Byrd had agreed not to offer it as an amendment to the bill rearranging relations with Taiwan only after obtaining a promise that he could get a vote on it later.

Two weeks ago the Senate voted 59 to 35 for Byrd's resolution rather than an alternative approved by the Senate Foreign Relations Committee that said the president could in certain cases terminate any treaty without Senate approval.

Senate leaders delayed a final vote on the resolution after a federal court here ruled that if, but only if, the full Senate acted on such a resolution would the court consider a suit by Sen. Barry M. Goldwater (R-Ariz.) - and others asking it to rule that the president cannot terminate a treaty without Senate approval. President Carter doesn't want such a limitation on the president's power to act.

Ever since, the resolution has been the pending business before the Senate, but a final vote has been continually delayed because administration supporters weren't sure they had the votes to pull the teeth of the resolution.

Yesterday, still not sure he had the votes to water down the resolution, Majority Leader Robert C. Byrd (D-W.Va.), replaced it as the pending business with a proposed constitutional amendment for direct election of the president.

This means the treaty resolution goes back on the Senate calendar along with all other bills approved by committees and awaiting Senate action. It can be brought up again by motion but that is usually considered the prerogative of the majority leader. The motion could also be filibustered.

After their defeat two weeks ago, administration supporters drafted an amendment to the Byrd resolution providing that it would apply only to future treaties. They believed this would cause the court to refuse to decide the issue in the Taiwan treaty case.

But Goldwater drafted another amendment, which would have been voted on first, that lawyers felt probably would cause the court to take his case and decide the constitutional question of whether the president can end a treaty without Senate approval. The Constitution says the Senate must give its consent by a two-thirds vote to approval of treaties, but is silent on termination.

Sen. Frank Church (D-Idaho), Foreign Relations Committee chairman, said yesterday he believed the Senate would have approved the amendment making the resolution apply only to future treaties if it could be brought to vote. But the leaders weren't sure they could defeat Goldwater, so they resorted to the procedural maneuver that put the resolution back on the calendar.