The best defense is a good offense, West German Chancellor Helmut Kohl thinks. His response to all the antinuclear demonstrators - and to those voices calling for a German version of ''two-key'' control of American missiles here - is a strong counteroffensive.
Is the public afraid of nuclear war and the dangers of deterrence? Then Dr. Kohl's Christian Democratic Union will organize its own peace conferences, and Kohl will explain (as at the major congress in Bonn Nov. 8) how the nuclear balance of terror has kept the peace all these years.
Are peace protesters cynical about the seriousness of American negotiating for Euromissile arms control? Then Kohl will scold such people for their ingratitude to the guarantor of West Berlin's security and the one-time provider of Marshall Plan economic aid to West Germany.
And are some Social Democrats (if no longer Kohl's conservative ally Franz Josef Strauss) calling for a German finger on the missile safety catch? Then Kohl will praise the virtues of existing American consultations with allies on nuclear issues.
At the end of the day he will count on the good sense of West Germany's silent majority to win out and tolerate (even if not cheer) the deployment of new NATO missiles beginning at the end of December.
The arguments about the nine Pershing IIs that will come to Germany and the 16 cruises each that will go to Britain and Italy next month have been nearly exhausted by now. But Kohl feels the pro-missile arguments have not had a fair hearing in the emotional public debate in West Germany. And he never tires of repeating them.
''We are not wanderers between East and West,'' he told the Nov. 8 assembly. West Germany belongs to the West. That means loyalty to NATO. And that means consistency in carrying out the NATO decision to deploy new American missiles in the absence of any prior Euromissile arms control agreement. Only thus can West Germany and Western Europe defend themselves against the Soviet ''striving for domination'' and ''monopoly'' of land-based Euromissiles.
In arguing that it is Washington and not Moscow that has been negotiating seriously, Kohl has recently been aided by Romanian state and party chief Nicolae Ceausescu. The Romanian leader, Kohl told a press conference Nov. 7, has written to Kohl, Reagan, and Andropov alike suggesting that British and French intermediate-range missiles be included in some later arms control forum and not at the Soviet-American intermediate-range (Euro-missile) talks.
Ceausescu's intervention is noteworthy, since Romania's ally - the Soviet Union - insists, and numerous West German Social Democrats concur, that the Soviet Union be allowed to have as many land-based intermediate-range missiles targeted on Europe as Britain and France together have in both land and sea basing - and that US missiles of this range be banned from Europe. This Soviet insistence is seen as the major block to any Euromissile arms agreement.
Kohl would like to draw a new demonstration of flexibility from Washington. At his Nov. 7 press conference he mentioned his expectation of a new US position in the remaining days before the mid-November recess of the Geneva talks.
US Undersecretary of State Kenneth W. Dam is on a swing of West European capitals this week to discuss just such a move. Indications are the final decision will be made when NATO's special consultative group meets in Rome Thursday.
Kohl did not give any details of a new offer, but US and West German newspapers have reported it would entail a global ceiling of 600 intermediate range missile warheads each for the Soviet Union and the US, with the US pledging unilaterally that it would not deploy the Asian missiles it would formally be entitled to.
This would mean in practice a European balance of 100 three-warhead Soviet SS-20s vs. 36 single-warhead Pershing IIs and 60-odd four-warhead cruises.
Some reports from Washington say this proposal - attributed to US chief negotiator Paul Nitze - has been rejected within the Reagan administration.
So far, Kohl has not had a major clash with supporters of a German ''two key'' system, in which a US missile based in Germany could not be fired unless both an American and a West German soldier released it.
To many West Germans, having a finger on the safety catch sounds too much like having a finger on the trigger. So far the idea has found little resonance here.