The unexpectedly large Senate vote for Kenneth Adelman was a tribute to the political powers President Reagan can muster when he chooses. He caused a majority of senators to take the extraordinary step of defying the recommendation of their Foreign Relations Committee, which had opposed the appointment of Ambassador Adelman to head the US Arms Control and Disarmament Agency (ACDA).
With this battle behind him the President can concentrate on achieving arms control itself. What better way to address lingering concerns of many senators - such as that Mr. Reagan displayed a lack of commitment to arms control by naming Mr. Adelman over some senior figure in the field?
The President can hardly doubt that he would have strong bipartisan support in pressing forward. Polls released last week suggested the depth and breadth of public concern for halting the arms race.
First came Harris Survey findings that Mr. Reagan's own supporters were prominently represented in the 79-16 percent majority of Americans who want Congress to call on the US to negotiate a sweeping nuclear freeze agreement with the Soviet Union. The survey cited a 78-19 percent majority of those who voted for Mr. Reagan in 1980 and a 72-23 percent majority of Republicans.
At the end of the week the latest New York Times/CBS News poll found a ratio of about 3 to 2 in agreement with Mr. Reagan that the Soviet Union is both a present danger and a growing threat. But respondents voted by 2 to 1 against military buildup as a spur to arms control. Here again Republicans joined in voting against their leader's tactics, by 50 percent to 33 percent. They also dropped sharply - from 59 percent to 46 percent - in approval of the President's foreign policy in general. Thus they helped bring his public rating on foreign policy to the lowest point ever, in contrast with other recent polls.
But the President has no doubt also noted how the public responded to a question on whether he was sincere about arms control or just using proposals to quiet his critics. The response - by 49 percent to 38 percent - was that he ''really means it.''
In other words, for all the recent controversies over his arms control policies, Mr. Reagan is still seen as sincere by almost half the public. This is something for him and Mr. Adelman to build on.