It is perhaps wiser to tune out what President Reagan is currently saying about arms control matters. Trying to parse his recent statements turns the brain to tapioca or black cynicism.

On Halloween, the president was interviewed by four Soviet correspondents. He told them that he wouldn't put his "Star Wars" missile defense system in place "until we do away with our nuclear missiles, our offensive missiles."

White House spokesman Larry Speakes said yesterday that what the president meant was that we wouldn't "share" Star Wars with other nations until we and they had eliminated "all offensive weapons." There would be a "transition period" during which the eligible countries would ceremoniously trash their nukes while we handed over to them the blueprints for "Star Wars" -- or "the star shield," as the White House prefers to call it.

Can't you just see it? Even, apparently, if the Soviets say "nyet" to scrapping their nukes, we and our allies would junk ours and snuggle behind the shield and tell them to buzz off.

This bit of fantasy followed hard on the heels of the president's "serious" reply to a Soviet proposal for a bilateral reduction of 50 percent in warheads. Included in his response was a suggestion that guaranteed its death at birth -- a proposal to eliminate mobile missiles, which would mean curtains for Midgetman, the mobile, single-warhead missile favored by neo-arms controllers on Capitol Hill.

Predictably, two Democratic members of Congress, Sen. Albert Gore of Tennessee and Rep. Les Aspin of Wisconsin, protested. The pair had bent themselves out of shape to vote for the MX on the grounds that, worthless as it is, the MX is needed until the the Midgetman is developed, a curious proposition put forward by the president's Scowcroft Commission.

Reagan perhaps enjoyed being attacked by Democrats for being too madly in pursuit of arms control. It's wonderful, if sick, public relations. But for people who hope that the president might be at least interested, it's mind-boggling.

In the meantime there has been no official clarification of the ABM Treaty's recent bizarre reinterpretation arranged by Richard N. Perle, the implacable foe of arms treaties.

Perle deposed that the treaty does not preclude testing of space weapons, especially since the Russians have been "ambiguous" about their understanding of it. When ABM negotiators began to howl, the secretary of state, who cleans up after the administration's hawks, said we would abide by the general understanding of the treaty, even though we didn't really need to.

Reagan pushes ever more deeply into Fantasyland, making ever larger claims about the blessings of Star Wars. What he likes best about it, obviously, is that it spooks the Soviets.

If Reagan were to settle for a simple reduction in arms, it would cost him little more than the plane fare to Geneva. Star Wars will cost a trillion dollars, and many eminent scientists claim it's looney tunes. Is it a solution to the political and emotional turmoil that negotiations would cost him? His right-wing constituency would be outraged at any show of accord with the lying, cheating Russians. The military-industrial complex, which is poised on the brink of unspeakable profits, would be infuriated.

So at the center of his arms-control position is this celestial equivalent of the Gramm-Rudman-Hollings budget-cutting contraption, which also puts into motion vast mechanical complexities of dubious capacity. Star Wars is the long way home to arms control, if indeed it is that.

Meanwhile, the summit is proving useful as a club to beat Congress into submission on military spending. A modest cut in the Star Wars funds was defeated in a House committee, and a sudden vote to cut out 12 MX missiles was instantly reversed. The rationale in both cases: if Reagan is to stand tall at the summit, he must be armed.

The current Washington wisdom is that, despite enormous and growing evidence to the contrary, Reagan really wants an agreement. This hopeful view is not based on the record, but on a romantic rumor that Nancy Reagan, though she has never said a word about nuclear war, is concerned about Ronnie's place in history and wants "Peacemaker" on his record. But the way he seems to see it, Reagan gets the inscription for Star Wars.

This is one time when the fine print is less important than the big picture. The Soviets have a leader who professes to want to divert military spending into making Soviet life livable. They have neither the money nor the technology for Star Wars. There's never been a better moment for arms control -- if Reagan really wants it.