Word is quietly being dropped in the Senate cloakroom with grim implications for President Carter: the strong prospect of no action until after the 1978 election on the treaties turning the Panama.

The possibility of so deadly a delay signals a faltering of the White House "full-court press" to sell the treaty to a stubborn Senate and country. Intense Republican opposition is rubbing off on the two most prestigious Republican endorsers of the treaties - Gerald Ford and Henry Kissinger. Former President Ford has decided he will not testify for the treaty.

In the Senate's own subtle way, the word is spreading that the treaties are more vulnerable today than on Sept. 7 when they were signed at the Pan-American Union building. That theatrical signing ceremony apparently failed in its purpose: to galvanize national attention and reverse the antitreaty tide helped along by well-organized conservative forces.

Putting off a Senate vote would please most senators, particularly those up for reelection next year and most especially Senate Minority Leader Howard Baker. While Baker is suspected of inclining toward approval, that would not help his 1978 campaign for reelection in Tennessee, nor his probable 1980 campaign for the Republican presidential nomination.

Indeed, if Senate action on the treaties does not come before the 1978 election, the matter could very likely be shelved until after the 1980 presidential election. That would raise serious questions in Panama and Latin America about U.S. intentions, besides undermining Jimmy Carter's authority throughout the world.

Senate Majority Leader Robert Byrd, who is scrupulously keeping his own counsel, says nothing out loud to dash President Carter's hopes for Senate approval early next year. Actually, Byrd could well end up supporting the treaties. But he is largely responsible for the deepening perception in the Senate cloakrooms of a long, long wait.

Meanwhile, Republican sentiment building against the treaties has begun to engulf Ford, whose widely advertised presence as Carter's houseguest for the signing ceremonies angered some party colleagues. Partly as a result of that anger, the former President has confidentially informed Sen. John Sparkman (D-Ala.), chairman of the Senate Foreign Relations Committee, that he will not be able to testify in favor of the treaties.

Ford's regress constituted one setback to the administration. Another is looming in the person of Kissinger. Senators have learned that Kissinger is troubled about the treaties and wants a change spelling out U.S. rights to intervene militarily if th canal's neutrality is threatened. Neither Kissinger nor Ford, moreover, is happy that the United States signed away rights to build a future sea-level canal unless Panama itself approves.

Underlying these adversities is the Senate's guileful ways in using the calendar to duck difficult political issues. Sparkman has scheduled a maximum three weeks of hearings, ending Oct. 14 shortly before Congress quits for the year. There will be no hearings during the recess.

Given the emotional politics surrounding the canal issue, hearings are certain to be resumed next year. But Congress now plans an unusually late return on Jan. 17, and almost all of February is given over to election-year campaigning.

Intimates of the starkly realistic Byrd say he doubts whether the treaties can even get to the floor before late March or early April at best. That could well delay a vote until summer, on the eve of the congressional election campaign. Assuming no sudden national swing behind the treaties, Byrd by then will be under heavy pressure not to bring the treaties up at all.

At that point, unless the majority leader is certain of the required two-thirds vote, he would be in position to set the treaties aside - claiming more important work requires the Senate's attention.

This prospect signifies that Carter has failed to seize the initiative on the treaties. Furthermore, the closer the issue moves to next year's election, the harder it will be for senators to run against the anti-treaty tide. The newly troubled President must now confront the possible death of the treaties through inaction, with all that implies for the presidential leadership of Jimmy Carter.