With all the talk of nuclear freeze in the air, Leonid Brezhnev would be less than the politician he is if he did not try to take advantage of it. His announcement that the Soviet Union has stopped deployment of the SS-20 medium-range missiles no doubt is aimed at public opinion in Western Europe and the United States where a grass-roots antinuclear movement is gathering momentum. In practical terms, of course, the gesture has little meaning. The Russians have already deployed up to 300 of the huge SS20s targeted on Western Europe, giving them a decided advantage. That they should now feel they have enough is not surprising.
If Mr. Brezhnev's announcement is a propaganda ploy, it is at least better to hear world leaders talking about freezes and reductions than nuclear buildups and wars. President Reagan, too, has gotten into the public debate to score his own points. A total nuclear freeze, he told an audience in Nashville, ''would leave us and our allies on very thin ice'' - a statement many arms experts similarly would take with a grain of salt. He would, he said, go on negotiating for deep reductions of medium-range nuclear missiles.
The question is whether Mr. Brezhnev and Mr. Reagan will get beyond their rhetorical posturing to actually doing something about arms control. The idea of an overall freeze is far from a woolly one given the fact that the United States now has some 9,000 nuclear warheads and the Soviet Union 7,000 - enough bombs on each side to devastate the world many times over.
However, this is not to fail to recognize the practical problems which the President must take into consideration. Verifying an agreement not to produce nuclear weapons, for instance, would require so many inspectors and such open access as to be nigh impossible. Stopping production of weapons already half built, such as the Trident II submarines, would mean throwing people out of work and disrupting industries. Freezing arms at present levels might leave both sides feeling vulnerable (the Russians because they have most of their fire power in heavy land-based missiles and the Americans because they believe their land-based missiles are inadequate) and that might have a destabilizing effect. Then there is the issue of the imbalance in Europe, which even if it is not as great as the US claims nonetheless is a problem.
Yet, as a goal and as a point of departure in nuclear arms talks, the concept of an overall freeze has merit. It is certainly taking off with the public. While their government languidly lets the nuclear arms race run on, Americans are waking up to the dangers and senselessness of it, and they are speaking out. And, significantly, the politicians have begun to shed their inhibitions on the issue now that they see the public aroused. So far 17 senators and 122 representatives--one-sixth of the Senate and almost a third of the House - have signed their names to a congressional resolution calling for a ''mutual and verifiable freeze on the testing, production and further deployment of nuclear warheads, missiles, and delivery systems.''
Whether or not one agrees with the concept of a nuclear arms freeze, this growing public movement is salutary and encouraging. If nothing else, it focuses national and world attention on perhaps the most perilous and difficult problem of our times. It will have its political value as the President and other administration leaders find themselves under increasing pressure to tackle strategic as well as theater arms reductions with determination and vigor.
The people, in short, are right. It is time to get on with arms control. Mr. Brezhnev and Mr. Reagan would do well to heed their voice.