Washington — A new and more forceful Reagan presidency has been emerging this spring. Politically speaking, Mr. Reagan has been playing to his strengths, rather than compensating for his weaknesses.
The American President's stance has some parallels in the posture of Britain's Prime Minister Margaret Thatcher, whose ''toughness'' - departing from ''consensus politics'' of previous years - is largely credited with making her the favorite in that country's coming general elections.
But apart from matters of style, Mr. Reagan has been establishing a position designed to get as much from Congress as possible, despite a president's declining leverage during his third year. Even more important, Reagan's new forcefulness will put him back in touch with the constituency that brought him to the White House in the first place.
For many weeks now, Reagan has been emphasizing his more fundamental positions on defense spending, arms negotiations, Central America policy, and the Middle East. His current five-day trip to the Southwest included a stop in San Antonio for a Hispanic celebration. There, he was expected to ask for support for his Central America policy. Today, in Phoenix, Ariz., he'll address the National Rifle Association. Recently he has restated his positions in favor of school prayer and tuition tax credits.
''He's rebuilding his base,'' observes one political analyst, examining the overall mix of issues, audiences, and regions addressed.
The Reagan base includes the South, as well as Roman Catholics and Southern working-class whites who want tuition tax credits or prayer in the school, and who usually register as Democrats. It tends to be male - with men more responsive to defense spending and a confrontational style than women are. The South, with its concentration of fundamentalist Christians, is more responsive to Israel's cause. The South is also more concerned about Central America's importance to the United States, as are male Americans generally.
Also crucial, Reagan's standing with voters generally has been more stable than that of his recent predecessors, analysts say. They note that he has not been forced into a defensive, catch-up posture. At this time in President Carter's third year, the Democrat had already faded once in popularity and had revived his standing with a Camp David success. Reagan can afford to risk - for the time being - some of his capital with the Northern tier of states, with women, and with minorities - his areas of weakness - and hope to catch up later, this reasoning goes.
By going with the issues he feels most comfortable with, and the groups that helped win him the White House, the President can use this spring and early summer to find out just how much clout he still has as chief executive. This should help him make a decision in August about a second term, aides say. The key factor in that decision: whether the White House offers Reagan a continued robust forum for change, or whether reelection would entail increasing compromise and less room for maneuver.
Neutral observers say some of Reagan's recent speeches - most notably the April 27 Central America address to a joint session of Congress - have been among his best, showing a welcome moderation of tone and emphasis.
''It was a dynamite speech,'' says Thomas Mann, executive director of the American Political Science Association, of Reagan's Central America address. Everett C. Ladd, director of the University of Connecticut's Roper Center, describes the speech as a model in forthrightness and explanation.
Despite the speech, the President has so far failed to get all he wanted in Central America aid. As with all his foreign policy addresses recently, the mere focus on international conflict apparently raises war fears.
''Between our January poll and April poll, the fear of war rose, particularly among women,'' says Kathy Francovic, manager of public surveys for CBS. ''Over that period, Reagan gave several major foreign-policy addresses. They weren't hawkish speeches - they were moderate speeches.''
So far, most analysts have looked at the negative side of Reagan's ''gender gap.'' But there's a positive side, too.
''Most of us look at the gender gap in terms of women,'' says Ms. Francovic. ''But the question may be not why women don't like Reagan, but why men do. Maybe we need a theory of a male political psyche to explain it.''
A ''male'' style of assertiveness, greater tolerance for confrontation, and a clearly outlined bargaining stance may not set well with some of the public. But Reagan's presidency this spring seems to be following that pattern.
Reagan's ''Sunbelt strategy'' can readily be explained in direct political terms. Large states like Florida and Texas are rated as tossups for 1984, and are essential to a Reagan victory.