Politics in the superpowers; Reagan defies the 'third-year slide'

Washington's morning rush hour traffic is thinning. In this town, that's as sure an indicator as any that the calendar has begun to impose its inexorable leverage on events.

Summer's coming. And the White House, Congress, and Democratic presidential contenders are maneuvering to complete their June chores before the public's attention to politics wanes in the summer sun.

The Reagan team feels it's had a good spring. It takes comfort from British Prime Minister Margaret Thatcher's conservative victory last week in the United Kingdom. Set against Britain's high unemployment, Mrs. Thatcher's win showed a high voter tolerance for austerity. But the White House also acknowledges that as yet President Reagan has had no event quite like Britain's Falklands crisis to hype his standing with voters.

Nonetheless, Reagan's voter-approval chart since January has defied the third-year slide of his predecessors back to Eisenhower. Elected Presidents Carter, Nixon, Kennedy, and Eisenhower averaged a seven-point drop from January through May their first term. Reagan has gained nine points over that period this year in the Gallup Poll. And he improved in virtually every subgroup, including women, union households, and Democrats. At 46 percent approval, he's only four points behind Nixon at the same point, though well behind Eisenhower ( 69 percent) and Kennedy (65 percent).

Reagan has benefited mostly from the economic recovery, aides say. But he has built on that by seizing the initiative on key topics like Central America, arms control, and the budget - or at least holding a strong enough position to drag the issue into stalemate, where he can wait out the other side.

The President's August vacation will be the big White House event of the summer. Out of it will come Mr. Reagan's decision on reelection. That decision will have an impact on other pending issues - arms talks with the Soviet Union, deployment of new missiles in Europe, the budget debate at home.

Events so far have cooperated with the Reagan calendar. He has not had to endure a domestic embarrassment like the gasoline shortage in early 1979, which forced President Carter into a desperate July effort to revive his flagging presidency.

Congress and the Democratic contenders have been at a disadvantage against Reagan.

''The President, speaking with one voice, always has an advantage,'' observed Sen. Lloyd Bentsen (D) of Texas, chairman of the Democratic senatorial reelection campaign for 1984, at a breakfast meeting with reporters. Eventually, however, the President also bears the political responsibility for his dominance of the political scene, Senator Bentsen says, when the eventual election becomes a referendum on him and his party.

Congress as an institution has improved its standing with voters over four years ago, when only 1 in 5 approved its performance. But Reagan's current 46 percent positive rating is well ahead of Congress's 33 percent in the Gallup surveys, suggesting useful leverage for Reagan in the budget impasse.

Congress over the weekend was working to blend the Senate's $850.1 billion budget for fiscal 1984 with the House's $861 billion budget. The compromise, splitting their difference over defense to arrive at a 5 percent arms buildup rate, seems certain to provoke a Reagan veto. Congressmen have their eyes on the July 4 summer recess. They've already put off consideration of the MX vote, which will require them to take a closer look at Reagan's newest arms negotiations offer.

The Democrats also look to the calendar to explain Reagan's high visibility and the low public interest in the Democratic nomination.

''This is June of 1983, and you bet they're ho-humming,'' Senator Bentsen says of the public's inattention to the Democrats. ''This is the formative stage'' of the Democratic race, he adds.

Just how formative the Democratic race is was shown this weekend when Sen. Alan Cranston (D) of California upset frontrunner Walter F. Mondale in a Wisconsin Democratic convention straw poll.

''Regardless of the field, there's still a 25 or 30 percent chance neither Walter Mondale nor John Glenn will be nominated,'' says a key Democratic strategist.

Republicans tend to think Mr. Mondale will prevail for the nomination, even though they add that Senator Glenn might have more potential for the general election. Yet one Republican professional says: ''Glenn's ratings are much like (Tennessee's GOP Sen.) Howard Baker's in '80. They reflect a lot of name recognition. When you get to the primaries I see Mondale's strength come crushing through. Mondale's just strong. Still, Glenn can appeal to voters that nobody else among the Democrats does - specifically in the South and in the West.''

Traditional public inattention to politics during the summer means the Democratic race will become little clearer before fall, unless a contender stumbles.

''The public campaign hasn't begun,'' says Stephen J. Wayne, a White House expert at George Washington University. ''Mondale, Glenn, and the others are not really followed in the press.''

Reagan benefits from his ability to command attention, and from the prospect of a summer political hiatus. He may benefit, too, from the public's desire to have a successful White House team, after almost 20 years of declining confidence in the institution.

''People may be tired of throwing blame on institutions,'' Mr. Wayne suggests. ''But the mood may be short-lived. . . . Things could look different in the fall.