Who should control US nuclear weapons in Britain?

Although the forthcoming summit meeting in Williamsburg, Va., will grapple with economic problems, it may also be an occasion for dealing with some tough political questions. For instance, should Great Britain be granted a ''veto'' over the launching of United States nuclear-armed missiles - or aircraft - from British bases? Should the decision to launch these weapons in a crisis be shared in some way by the US president and the British prime minister?

Prime Minister Thatcher has sought to counter a public outcry against the scheduled deployment of US missiles by explaining that a US decision to fire its nuclear weapons based in Britain cannot be made without the consent of the British government. Under arrangements of many years' standing, she claims that a decision to launch either missiles or aircraft must be a ''joint decision'' and this, she declares, is satisfactory.

But this explanation has not silenced critics. Recent polls show a clear majority opposed to deployment of the US missiles - partly because of lack of confidence in US control. As a result, reports have circulated that Prime Minister Thatcher might seek a British veto over the firing of the missiles from the US president. Or, if this fails, she might request at least US reaffirmation of the ''joint decision'' agreement.

The difference between a ''joint decision'' and a ''veto'' might appear to be semantic, but each rests on substantially different premises which politically could have a far-reaching impact in Britain and on other NATO countries.

The ''joint decision'' arrangement between the US and Britain dates back to the early 1950s when Truman and Attlee, and then Churchill, agreed that the use of air bases in Britain by US bombers in an emergency would be by ''joint decision'' in the light of prevailing circumstances. This arrangement now applies to the planned sites for 160 US cruise missiles at Greenham Common and Molesworth.

But the lack of any direct British control over the missiles themselves or their warheads does not satisfy many Britons. The present arrangement contrasts in their minds with the ''two-key'' control for the US-made Thor missiles deployed for a short time in Britain about 20 years ago (1958-1963).

At that time a British guarantee of an ability to control, that is, to prevent a launch if it wished, was assured when the US transferred ownership of the Thor missiles to the British while retaining ownership of the nuclear warheads. Thus a true duality of control was established by a duality of ownership. Both governments had to consent in order to fire the missiles.

Thus far, however, the Thatcher government has rejected purchase of the US cruise missiles, minus the warheads, which could establish dual control, even though the US government at one time reportedly offered to sell. Budgetary stringency and an already severely strapped defense account have been advanced as reasons. As an alternative there are reports that the prime minister might ask President Reagan for a ''veto,'' meant in the US to connote a legal right directly to block the launch of US-owned nuclear missiles.

That, however, could pose serious constitutional questions for President Reagan. First, the US president as commander in chief has the sole authority to authorize the firing of US nuclear warheads. But he can delegate it - as is evidently planned for certain emergencies and for wartime.

Does that mean that the president could delegate his authority or part of it to the British prime minister or another British official, thus permitting a veto? No, because that would be an unconstitutional divestiture of his power as commander in chief. He can delegate the authority to fire warheads only to others over whom he has legal control and from whom he can retrieve the authority at will. Members of the US defense establishment fall into that category. Officials of other governments do not.

Second, could the British government be given control if the US nuclear warheads were just given or sold to it? No, because US law (the Atomic Energy Act) forbids the transfer of US nuclear warheads to other governments.

Third, could the missiles, as distinct from the warheads, be transferred to the British government? Yes, under US law, providing the procedures for obtaining congressional authorization are observed, missiles, aircraft, or other vehicles for delivering nuclear warheads can be transferred by the US to the ownership of other governments.

However, at this time there are serious political and military reasons for not doing so. One of the main reasons for planning a US-owned intermediate-range nuclear force in Europe is to ''couple'' the nuclear defense of Europe to the US-based strategic deterrent. If the European governments shared in the ownership of and in the decision to launch intermediate-range weapons against the Soviet homeland, the coupling effect could be canceled or diminished, thus frustrating one of the main objectives of the NATO-approved deployment.

A second reason is that the planned deployment of the missiles is the result of a NATO decison - not just a US-British agreement - for the defense of the entire alliance. A discordant effect could result if one country could block, by whatever means, the launch of missiles which the other countries of the alliance might decide in an emergency to be necessary for their survival. Moreover, a yen for increased control could spread to other countries where it could fuel already aroused popular resistance to the deployments.

So, if Washington is faced by a British government request for some strengthening of its image of control over the cruise missiles, the best practical alternative for the US could be a strong reaffirmation of the current arrangement, essentially a pledge to take British views into account in the light of prevailing circumstances when the time comes for a decision. This would evidently be in harmony with NATO plans for general consultation on use of nuclear weapons in a crisis.

It is almost a sure bet, however, that such a reconfirmation will not quiet the continuing objections in Britain to the advent of the missiles. The sole sure-fire way to help the British out of their dilemma is not some new arrangement for controlling the missiles but a convincing step toward getting rid of the missiles themselves by a successful fulfillment of NATO's 1979 decision to negotiate an arms control agreement.