President Reagan enhanced his position as a leader of the Western powers at the seven nation economic summit held here over the Memorial Day weekend. As a result, he also may have boosted his political standing at home.
Mr. Reagan's aides note that his position in public opinion polls is growing stronger, thanks in large part to economic recovery in the United States. This trend, plus the added lift from his role here, should keep him in a strong position into the summer, when he is expected to decide whether to seek a second term.
The summit outcome also is likely to strengthen Reagan's hand with Congress. A rebuff of Reagan by America's economic and defense partners could have emboldened Congress as it continues to debate the budget and United States arms policy.
Instead, in colonial Williamsburg's setting of fine old brick-and-board buildings - a splendidly restored reminder of America's cross-Atlantic origins and maturity as a democracy - Reagan won endorsement of a common arms negotiation stance toward the Soviet Union, largely along policy lines the US favors. For the first time, France and Japan were included as cosigners of such a statement.
And, steering through a rocky course of criticism of US deficits and interest rates, he won endorsement of his conservative economic agenda, which calls for noninflationary growth in the West and a slow, ''sustainable'' recovery from world recession. He conceded little in policy terms to bids for monetary system reforms, or to widely held fears that the fledgling US-led recovery will do little for European unemployment.
But the Reagan arms and economic initiatives succeeded at a price.
Much as Reagan had to assure moderates in the US Congress last week he would use their approval of MX missile development mainly to bargain for arms reducations with the Soviets - a logic that nonetheless troubled many Reagan critics in Congress - Reagan again had to stress negotiation with the Soviets in the Williamsburg statement. This helped balance more hawkish phrases, like a warning to the Soviet Union that ''we shall maintain sufficient military strength to deter any attack, to counter any threat, and to ensure the peace.''
The result was a patchwork of postures that mingled the stern with the olive branch.
''We believe that we must continue to pursue these negotiations with impetus and urgency,'' the Williamsburg statement said. ''In the area of INF (intermediate-range nuclear force reduction talks), in particular, we call upon the Soviet Union to contribute constructively to the success of the negotiations.''
On the economy, each of the leaders of the other six delegations, plus the European Community, took issue with one phase or another of US economic policy - if not the strong dollar, then what they perceived to be Reagan's failure to see enough of a link between big deficits and the prospect of a shortened recovery.
Despite these signs of disagreement, Reagan can now look ahead to his California vacation in August when he is expected to decide whether to run for a second term. A first, nonbinding budget resolution is expected to pass by the July 4 congressional recess. There are few other tests for Reagan before his reelection decision time nears. He will make domestic political trips before August and will shortly introduce new education policy initiatives.
The White House sees the Williamsburg outcome as strengthening Reagan's current political position.
''We're on a roll,'' says a Reagan aide. The White House points to the President's recent modest rise in the polls as a sign he is avoiding the disastrous third year slide in approval that hurt President Carter. Reagan's strengthened approval rating is largely linked to public optimism about economic recovery, aides say.
However, the White House also acknowledges it has deliberately taken steps to avoid a third year slump by courting Reagan's conservative, Southern, white, and Hispanic electoral base in recent months. They ''revved up his base'' to avoid a decline in Reagan's popularity, which could have led Congress and the leaders of the other powers at the summit to more rigorously test the President's political strength.
Reagan's strategists have concentrated on this base at the risk of not building bridges to women and moderate Northern industrial state voters, whose support Reagan cannot write off should he decide to run again. In fact, Reagan's soon-to-be-announced education proposals are partly geared to women voters by showing more of a ''caring'' side to the President.