Set aside for a moment the raging debate over nuclear arms control and listen in on a related argument, less apocalyptic in its language but no less crucial to U.S. security. The question in its simplest form is whether the democratic, free-enterprising, fiercely sovereign states of the West are capable of building and paying for effective conventional defenses against the disciplined, totalitarian East.

It was little noticed, but the U.S. Senate answered the question the other day with a resounding No. By a vote of 81-to-1, it passed a resolution offered by Republican Sen. William Roth of Delaware, in the company of two of the Senate's most respected Democratic defense experts, Sam Nunn of Georgia and John Glenn of Ohio, which would have President Reagan present the problem in dramatic terms when he meets with his fellow government chiefs at the NATO summit in Bonn week after next.

The Senate resolution (a companion measure is before the House) states "the sense of the Congress" that the president propose nothing less than a revolution in the military procurement policies of the allies. They would be asked to agree to an unprecedented redistribution of the burden as well as the benefits of defense spending "to create, at acceptable costs, a credible, collective conventional force."

That means sharing everything--the liabilities (defense outlays) and the assets (jobs, technology, trade). The idea would be to cut costs by alliance-wide competitive bidding; to eliminate the gross duplication inherent in 14 separate defense efforts which leave many producers either foundering or subsisting on destabilizing arms sales to the weapons-hungry Third World; to get a bigger bang for fewer pounds, marks, francs, lira, or bucks by mass-producing for the whole alliance the best of those hardware items now being produced for narrow national markets.

It's a beautiful idea. It is also one that you might suppose would appeal mightily to an administration struggling to find money for massive defense buildups, eager to encourage a proportionately bigger European effort, and wedded to a strategy of nuclear deterrence in which beefed-up conventional armies, navies and air power play a critical role.

But it is also an idea ideally suited only for the best of all possible Free Worlds. It is less well suited for an alliance whose members take powerful pride in their own national defense capabilities, their own technology, their own military independence. The defense-industrial upheavals that would be involved are still less suited to a time when soaring unemployment is the curse of most alliance economies and rampant protectionism is a growing threat.

To see why, you need only examine a quite contradictory tendency in Congress, nicely encapsulated in the case of just one defense contractor, but a big one, by the name of E-Systems, Inc., with headquarters in Dallas and plants in both Indiana and Florida. When E-Systems recently lost out (by some $7 million) in competition with an Israeli firm called Tadiran on a contract for nearly $40 million in two- way radios for jeeps, tanks and other vehicles, it did not exactly give in gracefully.

On the contrary, it appealed to the General Accounting Office for help and prompted Indiana's Republican Sen. Richard Lugar to draft an amendment that would have specifically reversed the outcome. Possibly because his amendment was too blatantly directed to E-Systems interests, it was not pushed. But the powerful majority leader of the House, Rep. Jim Wright of Texas, is arguing the E-Systems case from higher ground.

He's got a much more all-encompassing amendment that would threaten the whole system of U.S. government agreements with allied arms suppliers by banning those that would allegedly make the United States dependent on a single foreign source. The theory is that E-Systems, if it loses out, would have to close down its production of these particular two-way radios and that dependence on a single Israeli outlet is too precarious.

But the Defense Department is not objecting. The State Department values the diplomatic utility of overseas procurement deals and opposes the Wright approach. You do not have to be a hopeless cynic to suspect that a large issue in all this for Congress is the welfare of American defense suppliers and their workers.

So in Congress there are two warring tendencies at work--protectionism and the Roth-Nunn-Glenn effort to "establish a cooperative (allied) defense-industrial effort.'

Which leaves the White House where? Straddling, judging from a White House answer to a letter from Roth last April. Roth was told the president would need a clearer signal from Congress before raising the issue at Bonn.

Heartened by the subsequent overwhelming Senate vote, and by a talk with administration officials, Roth last week wrote another letter to the president, pressing his case and suggesting that the president announce at the NATO summit the appointment of a special ambassador, outside bureaucratic channels, to pursue the possibility of integrating NATO's collective defense industry. What Ronald Reagan does about it (if anything) will be a measure of his alliance leadership.