Who set off the nuclear freeze?

Ronald Reagan is not the first United States President to think that some sinister foreign influence lies behind a popular movement running contrary to his purposes.

Mr. Reagan is contending now with a massive popular movement to ''freeze the bomb.'' It has swept across the country. It has pushed resolutions through many a state legislature and scores of town halls. It is a vivid cause among the great Protestant denominations. The Roman Catholic hierarchy in the US is likely to give it decisive endorsement.

The movement is having an important political effect. White House advisers recognize that the only way to defuse it is for the President to get into serious negotiations with the Soviets over limitations on weapons. If it was not politically imperative before, it is politically imperative now that the President give convincing evidence that he wants a SALT II, or a START, agreement with the Soviets.

Besides, the President's opening position must itself be convincing evidence of a sincere desire to arrive at a fair agreement.

Mr. Reagan's emotional reaction to all of the above came out in a speech he made to veterans' organizations in Columbus, Ohio, on Oct. 4. He said that the movement was ''inspired by, not the sincere, honest people who want peace, but by some who want the weakening of America and so are manipulating honest and sincere people.''

Presidents Lyndon Johnson and Richard Nixon also contended with a highly emotional popular movement which hurt them politically and interfered with their policies and purposes. The ''peace movement'' began during the Johnson administration. It plagued the President. It was an important factor in causing him to decide to back out of the 1968 presidential race.

Lyndon Johnson, like Mr. Reagan, suspected foreign influence behind the movement. He instructed both the FBI and the CIA to hunt for the foreign perpetrators of the movement which was portraying him as a war-making rather than peace-loving man.

Richard Nixon felt the pressure of the peace movement from the moment he entered the White House. It never gave him any peace. Like his predecessor he ordered both the FBI and the CIA to find out who was behind it.

There were other factors behind the political downfall of Richard Nixon, but the peace movement and his reaction to it were woven all through the fabric. It was his frustration over that movement and the pressure it was putting on his politics which caused him to order the ''plumbers'' operation for spying on Americans. The discovery that he had in fact been using the investigative agencies of the government to ''spy'' on Americans was one of the major counts against him when matters were moving toward impeachment in the House of Representatives.

It is possible, even probable, that had there been no peace movement to harass Mr. Nixon he would not have done the things which forced his resignation. Had he ended the Vietnam war by 1972 he might well have served out his second term peacefully and with general credit.

Both the FBI and the CIA did their utmost to find some sinister foreign inspiration behind the peace movement of the late '60s and early '70s. If something could have been found it seems likely that it would have been uncovered.

The essential fact about the peace movement which plagued Presidents Johnson and Nixon is that it was caused by the nature of the Vietnam war, not by sinister or foreign influence.

The war was unpopular for many reasons. The arguments for massive US involvement in Vietnam were never persuasively explained to the American public. Compulsory service in a remote jungle was unpopular, and unacceptable, without effective explanation. Television brought into the home not only the daily face of war with Americans being killed. It also showed My Lai and what Americans did to others. Public opinion was repelled and revolted. It wanted out.

The nature of the Vietnam war induced a mass peace movement. President Nixon could have defused it had he extricated the US from the war during his first term in office. He failed to do so. That failure was a large part of his political undoing.

The ''freeze the bomb'' movement of today dates from specific things done and said during the first year of the Reagan administration. There was the ''hard line'' toward Moscow, the arms buildup, the failure to pursue nuclear arms limitations, and, above all, talk from high administration quarters of ''fighting a limited nuclear war.''

The combination of those things frightened not only the American people but the allies as well.

There are indeed ''some who want the weakening of America.'' Moscow certainly wishes it. But there was no need for Moscow to manipulate ''honest and sincere people.'' The ''honest and sincere'' were frightened by Reagan talk into the freeze movement, without any manipulation.