After a conspicuous tilt toward Asia in his recent world travels, President Reagan now goes to Europe with a view to reaffirming the Atlantic Alliance, helping lay the groundwork for a sounder global economic recovery and - not incidentally - promoting his image at home as a world statesman.
The President's political planners do not hide their enthusiasm for a trip that will be rich in pageantry and opportunity for colorful television coverage. While the Democrats continue to battle for the presidential nomination, Mr. Reagan will be highlighting the news with his sentimental visit to Ireland, a ceremonial stop at the beaches of Normandy, and participation in the London economic summit meeting.
But as the President prepared to depart Washington today on his 10-day trip, administration officials were stressing the diplomatic importance of the journey more than its domestic political dimension.
The President's previous two journeys abroad were to Asia - Japan and South Korea last November, and the People's Republic of China in April. Washington has thus been visibly shifting its interest toward the region of greatest economic dynamism as well as growing strategic concern.
During the two Asian trips, a senior administration official says, the President forged a ''solid relationship'' with Japan and South Korea and opened up ''new opportunities'' in United States ties with China. Now, says the official, Mr. Reagan is returning to Europe to ''underscore once more the importance he places on the Atlantic partnership in both the political and economic spheres.''
Diplomatic and academic observers view the journey in the context of a recurring need to shore up the European alliance. The alliance is basically solid. But in light of the deep chill in US-Soviet relations, NATO members have been groping for various initiatives, including resurrection of the old idea of a European Defense Community, talks between West Germany and France on bilateral security integration, and such unilateral acts as the Trudeau peace initiative.
''Reagan must recognize that it is essential to touch base with the principal allies when they begin asking themselves where they stand with respect to the two superpowers, when they have an awareness of their own internal divisiveness and weaknesses, and when they see a US tilt toward Asia far beyond anything seen in other administrations,''says Charles Doran at the Johns Hopkins University.
''The Europeans want the impression to be given that the US is not turning its back on them,'' a State Department official says.
Solemn celebration of the 40th anniversary of D-Day in Normandy will provide the President an occasion to reaffirm the strong transatlantic link. According to administration officials, Reagan will recall the sacrifice made by the Allies and stress that reconciliation with former adversaries is possible. He will also emphasize that ''Allied solidarity and collective security'' have been vindicated by the long period of peace.
Throughout the trip, say administration officials, Mr. Reagan will point to the proven value of a ''renewed deterrence'' against Soviet power while making clear the ''flexibility'' in the American position and commitment to achieving arms reduction. This theme was also sounded by the President during the meeting of NATO foreign ministers here this week.
Urging the allies to remain firm in the face of Soviet efforts to divide on the deployment of new medium-range nuclear missiles, the President said ''our commitment to collective security will continue to be an indispensable bulwark against aggression, terrorism, and tyranny.''
When the Soviets decide to return to the arms negotiations, he said, ''we will be waiting, ready to meet them halfway.''
Although Reagan's trip has a heavy European content, its main purpose is the London economic conference of leaders of the seven major industrial democracies. Administration officials say the summit will not produce any dramatic agreements or declarations. It will simply continue the process of getting together annually to talk about critical global problems.Leaders can then be better informed and develop domestic policies that foster international economic stability.
Several key issues will dominate the London gathering: (1) how to sustain the world economic recovery and spread it to more countries; (2) how to cope with the world debt burden, aggravated by the rise in US interest rates, and ensure stability of the global financial system; (3) how to roll back protectionism and gear up for a new round of trade liberalization.
On the eve of the presidential journey, administration officials were playing up the economic progress made in the US since the summit meeting at Williamsburg in May 1983.
Treasury Secretary Donald Regan acknowledges that real interest rates are particularly high and that there is apprehension that the US will monetize its debt and inflate its economy.
But the President's position, he says, will be that the US recovery is ''much stronger than anyone believed possible,'' that there will be no ''resurgence of major inflation'' this year, and that the US has solved its unemployment problem ''fairly well.''
But many economists are not so sanguine about the gains made when measured against the objectives set at Williamsburg. They call attention to the huge US budget deficit, rising protectionism, still-high interest rates in many countries, slow growth of the European and Latin American economies, and high unemployment in Europe.
''On the centerpiece of economic growth we go into the summit with credit to our name,''comments Walliam Cline of the Institute for International Economics. ''But in specific areas there has been some failure to achieve what we talked about.''
The summit conference will also have a political agenda, the principal items of which will be East-West relations, the prospects for nuclear arms talks, terrorism, and the Persian Gulf conflict. On the latter issue, a senior administration official says, Reagan will assure summiteers that the Gulf states are able to defend themselves and that there is ''no immediate need'' for outside military help.
At the same time, says the official, Reagan will stress ''the value of careful, coordinated deliberation between ourselves and our allies'' and the need ''to harmonize our policies.'' The US is especially concerned that other countries reduce or eliminate sales of arms to Iran and Iraq.
France, for instance, is a large arms supplier. But despite US urgings to take a stronger stand on the Gulf crisis, the European allies appear reluctant to become involved in any coordinated military action in the Gulf.
In domestic political terms, the European journey gives Reagan strategists another opportunity to project the President as a gracious, effective world leader.
As on previous trips, a television crew from the Republican National Committee will be along to record the many photogenic events, from the President's visit to his ancestral home in the village of Ballyporeen to the ceremonies at Normandy. Clips will later be used for advertisements in the reelection campaign.
Reagan operatives note happily that there are 43 million Americans of Irish ancestry. ''The trip is not just for the benefit of Irish voters,'' says a campaign official, ''but for the millions of Americans who respond to their ethnic roots.''