Jesse Halms has now freed 25 of his 29 hostages, the diplomats whose nominations he held up for the last month while the State Department did his bidding in the case of six conservative appointees who had been threatened with loss of their jobs. The last four of the 29 are apparently to be released next week, once the State Department makes an announcement that the senator is expecting of it. The held-up nominees included the department's new undersecretary, four assistant secretaries and ambassadors to such sensitive spots as Israel, El Salvador and Iraq. Not a trifling list.

The temptation is to be glad the affair is over and to let it go. But for the Senate it is not over. Mr. Helms, the second-ranking Republican on the Foreign Relations Committee, has held up nominations before in his efforts to influence policy and personnel in the diplomatic and national security fields. He may do so again.

There is logic to the ornate customs of the Senate that give minorities of the membership and sometimes individuals the power to block or reshape majority rule. The majority's rule is moderated; there are hearings for lonely points of view. If the flip side is that the Senate is also roundabout and stuffy, that is the price you pay. The goal is to be deliberate in the best sense of the word.

But Mr. Helms takes the Senate beyond these tolerances; he goes to an extreme. He and the several conservative senators who joined him opposed some of the nominees on the merits. Most of the nominations were held up as pawns. Whatever they were meant for, the Senate's protective rules were not meant for that.

Mr. Helms is not an outsider in the Senate. His party is in control there, and in control of the executive branch as well; he is a committee chairman. He is abusing the Senate's patience and its rules. He makes the president seem indifferent and the State Department look weak and ineffectual. No senator wants to attack his fellows' prerogatives: when he weakens theirs he weakens his own. But it's time. Mr. Helms has become a marauder in these matters. If the president and secretary of state won't stand up to him, the Senate should.