"I hope," said Richard Moe, chief of staff for Vice President Mondale, "that this puts an end to all the stories about White House incompetence."

It was late Thursday afternoon, a few minutes after the Senate had approved the first of the two Panama Canal treaties. Moe and several colleagues were in the corridors of the White House West Wing, near the office of Hamilton Jordan, President Carter's chief political adviser.

"We've made some mistakes and deserved to take some raps," Moe said. But in the canal treaty vote, the vice president's top aide added, the Carter White House demonstrated that it could prevail on a difficult issue.

That was the prevalent view among the president's associates in the aftermath of the first canal treaty vote. But even as they enjoyed the glow of finally winning the big "victory" that so long eluded them, Moe and his colleagues must realize that winning one crucial test in the Senate does not wipe out the underlying problems of the administration or suddenly transform the nature of the Carter White House.

There is still a second canal treaty test coming up in the Senate and if White House aides are more confident of winning it than they are willing to admit publicly, there remains the chance that the president's victory of last week could all turn sour in the end.

Moreover, for all the inflated dramatics that went into the treaty debate and vote, the issue is far from the most difficult foreign policy question facing the administration.

One of the most difficult still facing Carter is negotiating and gaining Senthe Soviet Union. Viewed from the perspective of a future struggle in the ate approval of a new strategic arms limitation talks (SALT) treaty with Senate over a Salt II accord, the White House's experience with the canal treaty, according to one view, is not all reassuring.

"They are desperate for a victory. They have been desperate for a year," said one Carter associate just before last week's Panama vote. "Everything Jordan's office did on the canal treaty was a dry run for SALT. They pulled out all the stops."

Yet in the end, this source noted, the president was forced to accept amendments to the canal treaty - the kind of amendments the Soviets would not tolerate in a SALT accord - and was being publicly depicted as willing to give away the national treasury to the last reluctant senators whose votes he needed.

SALT will be far tougher and confronts the White House with an essentially different political situation than did the canal treaties. There is nothing Jordan enjoys more, or does better, than plotting strategies for the shaping of public and political opinion in the cause of Jimmy Carter. He did it in Carter's campaign, and he did it again in the long public-relations effort that led up to Thursday's canal treaty vote.

When the public-opinion polls finally showed sentiment flowing toward approval of the treaties, the White House wasted not a minute in letting the world know about it.

But, as Jordan noted to reporters after the Panama vote, when it comes to the threat of nuclear war and hope for an end to the arms race, public opinion is not the main problem. There remains strong sentiment in the country for detente with the Soviets. The problem will be in the Senate, where the technical details of a SALT II agreement will be subjected to a searching and skeptical examination.

Moreover, given the president's public statements of the last few days, it is by no means certain that the White House will get to chance to apply what it learned from the Panama debate to a Senate vote on SALT.

One year ago on St. Patrick's day, Carter addressed the United Nations, calling then for an end to the arms race and expressing preference for a significant cut in U.S. and Soviet nuclear stockpiles.

Six months ago, in a speech to a political dinner in Des Moines, the president blandly predicted that a SALT II agreement could be reached "in a few weeks."

But this St. Patrick's day, Carter was talking tough to the Soviets in a speech that had "bite," as Zbigniew Brzezinski, his national security affairs adviser, had hoped it would. The president's blunt warning to the Soviets to restrain their military buildup provoked a sharp response from Moscow, another sign of growing tension between the two superpowers.

For the White House, the largest impact of the Panama fight may be less externally in the president's standing than internally in what was learned about the weaknesses of the Carter staff and what will be needed for future fights, be they on SALT or domestic issues.

Jordan's decision to embark on a reshuffling of the White House staff - although its shape and extent are far from clear - grew in part from his experience in trying to mobilize administration resources behind the canal treaties. He learned firsthand then what outside observers have been saying for months - that, with a few exceptions, the Carter White House is thinly staffed, with too few people who can be counted on to execute the president's policies effectively.

"In the process of gearing up for a tough fight, we got organized, too," one aide said of the canal treaty experience.

"In the process of working on this, we met a lot of people," he added. "We found out that there were people anxious to help this president. That's been invaluable. Anyone who thinks we are not a hell of a lot stronger for it is wrong."