Perhaps it is only the glow of the season or a reflection from the superpower summit, but the Reagan presidency appears to have settled down coming into the homestretch.

The change has been striking. Within the past six weeks, President Reagan has backed away from unproductive showdowns with Congress on economic policy, the 1972 Antiballistic Missile (ABM) Treaty and the Supreme Court vacancy. Even Reagan's rhetoric, while less pragmatic than his conduct, has become calmer and less confrontational.

Last week the president gave another useful signal that he intends to take the high road in the final year of his presidency. Despite intense objections to an ethics law under which present and former aides have been investigated, indicted and convicted, Reagan signed a bill extending the system under which court-appointed independent counsels investigate high-ranking government officials. The measure could have become law over his veto or without his signature, but Reagan took the more appropriate course of upholding the statute while the courts decide its constitutionality.

The results of Reagan's actions suggest that a 76-year-old president dealing with an opposition Congress near the end of his second term can do best with a cooperative approach.

Reagan's high-court nominee, Judge Anthony M. Kennedy, is sailing toward Senate confirmation. Despite clamor on his right, the president also seems well-positioned in the Senate to withstand amendments that would sink the Intermediate-Range Nuclear Forces (INF) Treaty he signed with Soviet leader Mikhail Gorbachev. And the deficit-reduction compromise, while far more modest than it should have been, may have helped reassure jittery Wall Street that the sky will not collapse a week from Tuesday.

What has often saved Reagan from his ideological tendencies, as governor of California and as president, has been a political ability to recognize changing conditions and deal with them realistically. This skill deserted him, along with the "Reagan luck," during much of 1987.

It has often been said that Reagan failed to face up to the consequences of the Iran-contra affair, particularly to its impact on his overall credibility. But he faced up even less to the handicap created by the Democratic takeover of the Senate last year.

Reagan may have underestimated the Republican Senate's role in allowing him to control the political agenda during his first term. When Republicans lost the Senate, after a campaign that Reagan had made a test of his presidency, he advertised his weakness by adopting a confrontational "veto strategy" against the advice of his staff. When Congress overrode Reagan vetoes of water and transportation bills, it was a signal to the White House and the world that Reagan's magic had faded and that he had become an ordinary and vulnerable mortal.

Now, the spirit of the summit has boosted Reagan's approval ratings and given him a chance to finish strongly. Reagan's Cabinet is pulling in the same direction for a change. Even such formidable Reagan foes as House Speaker Jim Wright (D-Tex.) are talking about a "time for conciliation."

Reagan's recent foreign policy moves have been generally reassuring. He remains shakiest on economic issues, perhaps because the real world is giving him so much conflicting advice. Within the past two weeks, there has been good news on housing starts and the gross national product, bad news on the trade deficit and the dollar and mixed messages from financial markets and retail sales. A news magazine headline summing up the economy echoed the White House mood: "Confusion -- But Hope."

The hope here is that Reagan does not fall back on his old habits of blaming Congress for the deficit, which only invites congressional leaders to join in a never-ending and harmful game of pin-the-tail-on-the-deficit. Instead, the president should proclaim in his State of the Union message that he does not intend to engage in partisan name-calling while the economy falls apart at the seams. He should proclaim his willingness to set aside ideology and preconceptions to work with Congress to deal with a volatile economic situation -- and invite the opposition to practice the approach it preaches. This is the season and the time for reconciliation.

Reaganism of the Week: When he was applauded by bipartisan congressional leaders at the White House for his summit performance, the president said: "What happened? Did you just see one of my old movies?"