Is it easier to survive war than prevent it?

''Everybody's going to make it if there are enough shovels to go around,'' Thomas K. Jones, deputy under secretary of defense, has been quoted by the Los Angeles Times as saying when the subject turned to nuclear war. ''Dig a hole, cover it with a couple of doors, and then throw three feet of dirt on top. It's the dirt that does it.''

The Senate Subcommittee on Arms Control was understandably eager to have Mr. Jones elaborate on this most serene of scenarios for World War III. But the optimistic deputy under secretary failed to appear, after being scheduled to testify on three different occasions.

At least one member of the committee, Sen. Alan Cranston (D) of California, argues that the civil defense program being promoted by the administration fosters ''cruel and dangerous delusions.''

Certainly John D. Steinbruner, director of foreign policy studies at the Brookings Institution, has no visions of a three-feet-of-dirt war. Writing of ''Nuclear Decapitation'' in the current issue of Foreign Policy, he comes back again and again to the utter vulnerability of both the United States and the Soviet Union.

Will the present strategy of higher and higher stockpiles of deadlier and deadlier weapons close ''the window of vulnerability''? Not as Mr. Steinbruner sees it. In this case a strong offense is not the best defense. Mr. Steinbruner cites situation after situation in which the size of one's strike power would become irrelevant. For example:

''A very small number of high-altitude explosives (one to five) could subject the entire United States to short but intense electromagnetic pulses in the range of 25,000-50,000 volts per meter. Solid state circuitry of contemporary design, heavily utilized in U.S. military technology and in civilian technology, is particularly vulnerable to damage from these pulses.''

Is there any way at all to protect the sophisticated power circuits that make a modern nation so vulnerable? Mr. Steinbruner expresses doubt: ''A high confidence technical solution . . . probably cannot be achieved at feasible cost.''

Since the same holds true for the Soviet Union, more and bigger arms, Mr. Steinbruner implies, will only tend to create more and bigger areas of vulnerability, leading to ever more dangerous anxieties. Thus, ''Soviet leaders could be powerfully deterred from war'' by a massive US buildup, ''yet still conclude in the midst of crisis that war will inevitably occur against their will. In that case, they would be strongly motivated to initiate an . . . attack to reduce the damage they would ultimately incur.''

In a sentence that ought to be engraved on uranium Mr. Steinbruner writes: ''Deterrence and the prevention of war are not the same thing.''

What hope is there then? After his relentless consideration of every possible military strategy, Mr. Steinbruner concludes: ''A minimum diplomatic requirement must be preserved as an imperative of security.'' Not from idealism but from a pragmatic sense of unacceptable risk, he submits that negotiations must go on, however exasperating the process and imperfect the results.

By contrast, those who are rosy optimists about our chances of surviving nuclear war become black pessimists about our chances of negotiating a limited-arms agreement.

We all have our areas of hope and despair. For instance, a fellow in Utah wants to build elegant civil-defense condominiums so that Americans can survive in style, eating the very best canned shrimp, as he envisions it. What makes this optimist a pessimist is that he cannot market his Doomsday real estate because mortgage rates are so high.

Still, it is curious that people should judge surviving World War III a more likely event than preventing it. One would think that anybody who could believe in canned shrimp and three feet of dirt could believe almost anything.