West German Chancellor Helmut Schmidt is playing for the highest stakes of all in his talks with visiting Soviet President Leonid Brezhnev in Bonn Nov. 23 and 24.
He is seeking to persuade Brezhnev that this may be the world's last chance to negotiate nuclear arms control. He is trying to convince Brezhnev that he must seize the opportunity for the real security of the Soviet people as well as all mankind.
According to ranking officials here, Schmidt is telling his guest not to overestimate the power of antinuclear movements in Western Europe. Don't underestimate the goodwill of President Reagan. Don't believe your own Soviet propaganda. Don't let yourself be pushed deeper into an isolation that will be dangerous for all of us.
Do deal with Reagan, a kind and trustworthy man who is now making a serious offer of arms control, these officials say Mr. Schmidt is saying. Do realize that you are being given an opportunity unique in military history - a chance to negotiate away new (NATO) weapons before they are deployed and before the arms spiral is given another twist.
The real security of the Soviet Union - and its prosperity - could only benefit from mutual restraint. With your political system, you can, of course, afford more weapons. But even for you the economic and perhaps political costs will be high.
Think beyond narrow military advantage to your own conviction that nuclear war would be a disaster for all mankind.
Since you already have superiority in European continental nuclear missiles, he is understood to be saying to Brezhnev, you may not see much reason for restoring equality in the European nuclear arms control talks opening Nov. 30 between you and the United States. You may just wish to capitalize on your superiority and hope that popular antinuclear sentiment in Western Europe will defeat the new NATO missiles and leave you with an advantage.
If so, you will be mistaken. Not only will West Germany and the NATO governments (without the Dutch, if necessary) go ahead with planned missile deployments if you do not show some compromise. More importantly, you will have spoiled your one chance to engage the Reagan administration in serious strategic arms control, Schmidt is described as saying.
Many things are now in flux in Washington. Mr. Reagan has finally turned from his economic priority to make his first foreign policy speech. It was an offer of arms control in strategic as well as European nuclear weapons. It was a serious offer.
You, Mr. Brezhnev, have the choice of responding to the offer, or of squandering the next two years - and seeing another spurt in the arms race that benefits none and endangers all.
You are a superpower. You don't need to push on open doors to prove it. Statesmanship at this stage would be a far more persuasive sign of your greatness.
In giving this message to Brezhnev Mr. Schmidt is taking large risks.
The first risk is that the ailing and elderly Brezhnev may no longer have much impact on Kremlin decisionmaking. The second risk is that the whole West German effort may be mistrusted by the US as an attempt to carve out a special Soviet-West German relationship at the expense of Washington.
In calculating that the first risk was worth taking, West German policymakers have made several assumptions. They have observed that the Kremlin oligarchy finds it important to keep Brezhnev at the top, that it is not yet ready to loose the free-for-all power struggle that is likely to follow Brezhnev's departure. They therefore presume that whatever is said to Brezhnev and his policy adviser in Bonn will go directly to the Soviet Politburo.
The second assumption is that Brezhnev's personal experience in World War II and his stake in the detente that he himself engineered gives him and the present Politburo a greater incentive that their likely successors will have to agree to common restraint with the West.
At the same time Brezhnev's stature - as the 17-year Kremlin leader who redressed the humiliation of Nikita Khrushchev's Cuban missile retreat, brought the Soviet Union to strategic parity with the US, and gave it global military reach - means that the present Politburo could better implement any superpower agreement than a successor Politburo could.
The obverse assumption is that in the likely several-year period of a Kremlin struggle for succession, there will be enormous pressure on candidates for the top post to outscore their rivals by showing more belligerence toward the West. Any course of foreign policy restraint - of cooperative incentives to good Soviet behavior in addition to the confrontational disincentives to aggressive behavior - probably stands a better chance of surviving the transition if it is begun now rather than initiated by a shaky new leadership.
The third presumption is that Brezhnev and the present Politburo, while disliking Schmidt's words, will at least consider them soberly. Schmidt and Brezhnev have met six times now, and Schmidt's description of Brezhnev's view of him is that of a plain-speaking ''honest foe.''
This is far different, government spokesmen stressed, from any role as a ''middleman'' or a ''broker'' between the two superpowers, as the West German media often interpret it. Schmidt is a firm ally of Washington and - unlike a neutral middleman - makes it very clear in his dealings with Brezhnev.
Nonetheless the very fact that Schmidt is the first and only Western leader to be hosting and talking to Brezhnev after the Western ostracism of Moscow, following the Soviet invasion of Afghanistan, gives rise to some suspicion in Washington. This is Schmidt's second bit of risk taking.
The suspicion was succinctly expressed by the London Economist in its lead editorial this week while acknowleding that Schmidt ''has his feet firmly planted in the Western Alliance'' the Economist saw only dangers and no opportunites in the Schmidt-Brezhnev dialogue. It warned that Moscow was doing its utmost to weaken Bonn's ties to Washington and to freeze current Soviet nuclear superiority in Europe.