As arms control talks resume in Geneva and the dates for the construction and deployment of more missiles approach, there is increased questioning of the military usefulness of nuclear weapons.
This is the basic concern underlying the bipartisan ''build-down'' proposal being advanced in Congress, which would dismantle old nuclear warheads faster than new ones could be deployed. It is the main point the NATO commander, Gen. Bernard W. Rogers, has been making to all who will listen. It is implicitly acknowledged in the recent recommendations of the President's Commission on Strategic Forces (the Scowcroft Commission) and even in the Reagan administration's own arms control proposals.
Former Defense Secretary Robert S. McNamara, expanding on his controversial ''no first use'' thesis put forth 18 months ago, now argues that ''nuclear weapons have lost whatever military utility may once have been attributed to them.''
In a forthcoming article in Foreign Affairs magazine and in conversation with reporters this week, Mr. McNamara warns that NATO's reliance on the threat of nuclear weapons in response to a conventional attack from the Warsaw Pact ''carries with it a high risk that Western civilization, as we know it, will be destroyed.''
Reagan administration officials, former Secretary of State Alexander M. Haig Jr. and others assert that large numbers of nuclear weapons still are needed to deter a Soviet attack. In the early 1960s, McNamara himself drew up NATO's current doctrine of ''flexible response,'' which leaves open the option of being the first to use nuclear weapons.
The former defense secretary acknowledges that ''the question of what deters Soviet aggression is an extremely difficult one.'' But he says that the total inventories of nuclear warheads has grown so much (about 40,000 to 50,000 on both sides today) and their deployment so wide that the incentive to strike preemptively out of fear or miscalculation is far greater now.
''Is it realistic to expect that a nuclear war could be limited to the detonation of tens or even hundreds of nuclear weapons, even though each side would have tens of thousands of weapons remaining for available use?'' he asks. ''The answer is clearly 'no.' ''
In recent months, the same point has been raised frequently. One of the few weapons cut from the 1984 defense budget by Congress was a new type of nuclear artillery shell. Assistant Secretary of Defense Richard N. Perle has reportedly said privately that the NATO decision to deploy Pershing II and ground-launched cruise missiles may have been a mistake. The Scowcroft Commission unenthusiastically endorsed the MX missile as a necessary indicator of ''national will'' in arms control bargaining.
Sens. Sam Nunn (D) of Georgia, William S. Cohen (R) of Maine, and Charles H. Percy (R) of Illinois last week offered a ''double build-down'' proposal to reduce strategic weaponry. This would involve reducing total US and Soviet ballistic missile warheads from 8,000 to 9,000 each to about 5,000. Then a steadily declining limit would be imposed on ''overall destructive capacity'' (a combination of warheads, missile throw-weight, and bombers) to about half today's levels.
General Rogers, the European Security Study (a high-level group of academic experts and retired senior military officers), and others have said that for about $20 billion, NATO could rebuild conventional forces sufficiently to reduce its dependence on nuclear weapons. This would mean raising the alliance's goal for increasing defense spending from 3 percent a year to 4 percent.
McNamara agrees, but adds that more steps should be taken now: Cut NATO's tactical nuclear arsenal (mostly relatively old artillery shells) by half, to about 3,000; move the rest from their forward-basing areas, where they may be used early in a conflict for fear of being captured; and seek a verifiable nuclear-free zone in Central Europe.
He says the scheduled East-West conference on military confidence-building measures in Europe (to be held in Stockholm next January) would be the best place to discuss such issues.
McNamara, whose concern with the possibility of nuclear war has become a crusade of sorts, flew to Europe this week to consult with government officials and public leaders.
His essential message: ''I do not believe the average person in the United States or Western Europe has given enough thought to the risks that our societies are facing today as a result of the present policies and military strategies which we are dedicated to.''