In the first 100 days, Ronald Reagan built a glow of good feeling. He restored the morale of the majority. He showed appreciation for the great moments of the American past. He evinced gallantry in distress. So much more than mawkish sentimentality over the assassination attempt underlies the soaring of his popularity and the truly touching reception he received in Congress Tuesday night.

His program, however, is woven from unresolved conflicts of public opinion. The public hates inflation and blames it on government spending. So the president has called for truly draconian cuts -- 40 percent below present levels by 1984 -- in federal spending for assistance to education, food, housing, health and transportation.

The public wants lower taxes and faster economic growth and more jobs. In response, the president has backed as an economic stimulus a massive, three-year transfer of resources from the public to the private sector known as the Kemp-Roth tax cut.

The public also favors a firm stance against the Soviet Union. So the president has endorsed a huge and rapid hike in defense spending -- up from $163 billion now to $256 billion in the next three years.

Add bigger defense spending to a major tax cut, and there emerges a largish budget deficit -- about $50 billion. The deficit puts pressure on the Federal Reserve System to keep many rates high, thus curbing growth. Moreover, the administration does nothing to hold down wage bargains or energy costs. So there are implicit contradictions in the president's economic program.

Congressional Democrats have underlined the contradictions, James Jones, chairman of the House Budget Committee, put together a program that combined a rise in social spending with a cut in defense spending to end up with a smaller total outlay and a lower deficit. To fight the Jones package in the House, the administration has embraced a compromise known after its proponents as the Gramm-Latta amendment. Gramm-Latta reduces the administration deficit by driving social cuts even deeper.

The president has gone all out for the compromise -- first in telephoning the congressmen while convalescing, then on Tuesday night in his speech to Congress. The vote in the House promises to be the first major test of Reagan popularity as applied to programs.

Even if Reagan wins, however, he is only back to square one. He has yet to drive the budget through the major congressional committees and both houses of Congress. He has also to maintain Kemp-Roth, with its three-year tax cut, against a one-year cut put forward by Dan Rostenkowski, chairman of the House Ways and Means Committee, with impressive bipartisan support. So there is no chance the administration will get the quick, clean program it sought by July 1. Popularity or not, in other words, the president is still deep in the congressional woods.

Nor has popularity saved the president from being caught in the conflict between foreign policy and domestic politics. Secretary Alexander Haig, in the interests of a coherent policy, sought primacy of place for the State Department, particularly in the matter of crisis management. He tried to postpone any action in the Middle East, at least until after the Israeli elections on June 30. To keep the allies on board, and Russia under pressure, he wanted to maintain the grain embargo applied to the Soviet Union by Jimmy Carter after Afghanistan, and maintained by Reagan initially because of Soviet menaces to Poland.

But domestic farm interests opposed State on the grain embargo. The Pentagon and energy interests wanted to sweeten Saudi Arabia by promise of a major new weapons system -- the AWACS surveillance planes. The White House staff, led by Edwin Meese and James Baker, opposed Haig on crisis management.

In each case, the president let the conflict surge, and then sudenly made a decision on behalf of his domestic constituency. To keep his farm interests happy, he lifted the embargo. To appease the energy interests and the military, he decided to sell the AWACS to the Saudis. To keep the domestic interest foremost, he gave crisis management to Vice President George Bush.

By themselves, these decisions are not all that important. But the pattern suggests a White House unsure of itself on substance and politics. The impression is that the administration lacks a strategy for translating the president's popularity into support for his programs. It is unable to fend off conflicts or devise ingenious solutions. As a result, the pressures mount and the president lunges for a decision.

That is not a recipe for solving problems at home or abroad. So, after 100 days, and despite the enormous personal success of the president, the prognosis is for more of what there has been in the past -- slow growth and high inflation in the United States, and, in the world, turmoil.