It is hard to see how Ronald Reagan could have heightened the suspicion that he is allergic to arms control, but, by refusing to renominate Robert T. Grey Jr. as deputy director of the Arms Control and Disarmament Agency, he has done it.

The president withdrew Grey, a highly personable foreign service officer, with a record for competence and courage--he once sent a famous cable of dissent from Cambodia on the B52 bombing of that tragic nation--ostensibly under the threat of "blood on the floor" from that implacable right-winger, Sen. Jesse Helms (R-N.C.), if the nomination weren't withdrawn.

Politically, it doesn't make sense. The administration, through the strenuous efforts of Senate Majority Leader Howard H. Baker Jr. (R-Tenn.), had shown Helms who is boss during the recent lame-duck session of Congress.

It is not the custom to feed the vanquished such a rich order of red meat so soon after.

Baker told the president that he had the votes to move Grey's nomination--and that of Richard Burt, another Helms black-listee--and was willing to do so.

As late as Dec. 14, through his deputy press secretary, Larry Speakes, the president voiced "full confidence" in Grey. Now he has pushed him over the side, amid unconvincing murmurs that "you don't need to beat Helms every day of the week."

Grey is too much the professional to bewail his fate. He has no idea why Helms will not have him. They have never met.

Helms was not present at Grey's confirmation hearings last March, which "lasted all of three minutes."

The senator sent him a sheaf of written questions, and abstained from the 10-to-0 committee vote. He has been on the job and on hold for a year.

Sitting in the large, blue-carpeted office on the fifth floor of the State Department, the white-haired Grey says that his problem "probably has to do with me not having been on the long march with Reagan."

"A lot of them up there take a dim view of foreign service officers anyway," he said, with a notable absence of the stuffiness supposed to be the mark of his kind. "They think of us as guys with three last names. I confuse them because I'm a mick with an English name."

Grey's maternal grandfather was the fire chief of Boston. He describes himself, politically, as a "Jackson-Moynihan Democrat."

His offense may have been that he took two years off from the State Department to work for Sen. Alan Cranston, the California liberal and notorious advocate of arms control. Cranston, incidentally, voted against the confirmation of Grey's boss, Eugene V. Rostow, the director of the Arms Control and Disarmament Agency, because he found Rostow's nuclear views too hawkish.

Rostow, a conservative Democrat, is devoted to Grey, and noisily mourns the loss of "my good right arm."

Rostow put his finger on the harm the president has done himself: the sacking of Grey leads to doubts as to who is in control of arms control.

The capitulation to Helms, who espouses the classic right-wing view that no arms control agreement is verifiable, Rostow said, could cause "a fear response among the Soviet Union."

"The Soviets can try to exploit the doubts, and they get very anxious at the thought that any extremist American group might take charge of American nuclear policy."

More than that, of course, the Grey imbroglio reminds people that Helms' views on arms control are not that different from the president's. Helms says he believes, as does Reagan, that the Soviets lie, cheat and steal--and cannot be trusted in any sphere.

Since the death of Leonid I. Brezhnev, the president's attitude has invited renewed doubts. While Vice President Bush was making conciliatory remarks at the funeral in Moscow, Reagan was talking Cold War to German Chancellor Helmut Kohl on the South Lawn: "A power to the east has built a massive war machine far in excess of any legitimate defensive needs."

When the new Soviet leader, Yuri V. Andropov, made a negotiating offer, the White House rejected it as "propaganda" even before it was officially received.

More recently, when our chief negotiator, retired general Edward L. Rowny, came back from Geneva and spoke of a "50-50 chance of an agreement, the administration organized a bucket brigade to throw cold water on the thought.

The sophisticated opinion about the Grey case is that Reagan is sending a message to Rostow, who hinted that he would resign if Grey were dropped. Administration heavies disparage Rostow as aging and indiscreet. Rostow is said to be genuinely in favor of arms control.

Now, more than ever, people are wondering if the president is.

Grey says quietly about the brouhaha: "It is a problem they didn't need to have."

He will wait for his successor, then go back to the foreign service, having demonstrated that blamelessness is no defense when the right wing gets on your case--and you're doing a job the administration may not really want done.