Does the Soviet union's extensive--and very expensive--civil defense system give it the power to blackmail the United States in conflicts over our vital interests, or even to go to war with us?

Yes, it does, according to some analysts. They view the civil defense program within the context of Moscow's massive and increasing military expenditures, its deployment of certain tactical and strategic systems, its continuing research and development programs with counterforce applications and an opportunistic foreign policy.

In a nuclear war, they argue, the Soviet civil defense programs might allow that state to emerge relatively unscathed, while for the United States, destruction would be complete. Thus, they say, the United States must carry out a massive civil defense program as part of an effort to re-establish a credible and real deterrence.

This argument, I believe, tends to overstate the defensive capabilities of the Soviet Union, which in truth faces a number of problems with its civil defense program.

For one thing, the Soviet population is concentrated in a relatively small number of urban centers, and evacuation plans, never practiced on a large scale, are bedeviled by uncertainties about transportation, supply, climate and shelter. Soviet civil defense, in fact, would be unable to prevent massive and unacceptable population losses in a major attack, according to the CIA.

Moreover, the high concentration of Soviet industry within a few major complexes, the inability of the Russians to harden industrial sites effectively against direct attack, the primitive state of Soviet transportation and myriad other problems suggest that the Soviet economy would be ravaged in a nuclear war, and that prospects for recovery after the attack would be, at best, slim.

According to the CIA, these problems, in conjunction with the facts that a Soviet directive to put civil defense plans into effect would put U.S. strategic forces on alert (thereby strengthening their destructive capabilities) and that the United States could wreak unacceptable physical damage upon the Soviet Union in a retaliatory strike attest to the continued credibility of the American deterrent.

There would be other difficulties for the Soviets in the event of war, difficulties for which their civil defense program would offer few answers.

First, a major disruption of their centralized system of communication and political control might well jeopardize the continued internal political hegemony of the Communist Party, especially in light of increasingly nationalistic forces among many of the Soviet Union's non- Russian nationalities that are tending to pull them away from the dominant Russians.

Second, and related, is the geographical coincidence of Soviet ICBM installations, major Soviet industrial centers and concentrations of ethnic Great Russians. Even in an American counterforce strike, ethnic Russians would perish in numbers far greater than their current (although declining) percentage of the Soviet population--52 percent. It is likely that a nuclear exchange would disrupt and possibly end Russian control over the state political and military apparatuses, thereby threatening the continued existence of the multinational Soviet empire.

Finally, the continued allegiance of Warsaw Pact members to the Soviet Union, and Moscow's control over these nations, would certainly be called into question in the event of nuclear war.

Thus a nuclear exchange with the United States would result very likely in great physical suffering for the Soviet Union and an end to its superpower status.

Civil defense in the Soviet Union serves a number of political and ideological functions, and it is quite consistent with the Soviet concept of deterrence. It should not be interpreted to prove that the Soviet Union does not subscribe to deterrence as a means of avoiding war with the United States, or that it is no longer deterred.

The Soviet Union is still deterred by the substantial flexibility and capability of the U.S. nuclear arsenal, which is able to mitigate any marginal benefits of the Soviet civil defense program.

It would be too costly--both economically and politically--and of marginal value militarily for the United States to duplicate the Soviet civil defense programs.