Did summit boost Reagan politically?

Flash polls after the Iceland summit indicate strong support for President Reagan's performance, despite the disappointing results of talks with Soviet leader Mikhail Gorbachev. Republican strategists, anxiously eyeing nationwide elections in just 19 days, say several overnight polls on Monday and Tuesday found that the President's popularity climbed sharply after the summit.

Mr. Reagan has been deeply involved in the battle for control of the Senate in the Nov. 4 elections, and his popularity could be pivotal to Republican chances. But even with the President's higher approval ratings, GOP pollster Richard Wirthlin concedes that the contest for the Senate could go either way. He observes:

``I have never seen so many states so close and so undecided so late in the game.''

Dr. Wirthlin says that Senate control could hinge on seven states -- and that either party could conceivably win them all: Florida, North Carolina, Louisiana, Missouri, Colorado, Idaho, and California.

Wirthin, who met with reporters over breakfast here, said his best current estimate is that the GOP will hold the Senate by a 51-to-49 margin after Nov. 4. But he concedes his polls and others by Republican consultants show only a ``razor-edge margin'' for the GOP.

Republican political planners had shivers when the Iceland summit broke up on a chilly note. A sudden drop in the President's popularity could have an impact on both Senate and House candidates across the country, Republican consultants say.

But it now appears that will not happen.

Wirthlin's polls just before the summit found that Americans, by a 64-to-34 margin, approved of the way Reagan was doing his job.

By Tuesday night, after the summit, the margin of approval had risen to 73 to 27.

One reason is that Americans apparently agree that the summit, despite outward failure, helped both sides recognize areas where future agreement might be possible. Only 18 percent of those sampled on Monday and Tuesday thought Iceland was a setback for arms negotiations, while 80 percent thought it moved the process forward.

Why weren't Americans more upset about the breakdown of talks? Wirthlin explains that most Americans are ambivalent about the Soviets. They want to talk to them, and sign agreements. But they also don't trust them. And many Americans believe that Reagan feels the same way they do about the Soviets.

Apparently that is why 68 percent of those polled Tuesday night felt Reagan had not missed a chance for a meaningful agreement, Wirthlin said. The public seemed to feel: If Reagan thought it wasn't a good deal the Soviets were offering, then we shouldn't take it.

One additional effect of the summit: Public approval of the President's Strategic Defense Initiative, or ``star wars,'' rose by 12 percent (to 74 percent). Disapproval fell from 36 percent to 24 percent.