Ronald Reagan was the picture of summer ease as he strode onto the stage of Constitution Hall to address the American Bar Association convention. He was wearing a light tan suit, a light blue shirt and an expression of cheerful confidence.

If he had any concern that he may have lost standing in the wake of the inglorious Beirut hostage episode, it was dispelled by the standing ovation that greeted him. As the Marine Band struck up "Ruffles and Flourishes," a huge American flag rippled across the ceiling and then dropped down to loud applause, which swelled as the president took a bow. To lawyers, as to other Americans, Ronald Reagan apparently has become the stars and stripes forever.

By his own oft-stated, Rambo-like standards, the hostage crisis was a downer. There was none of the threatened "swift and effective retribution"; there was instead a positive panic to deal. During the 17 days the hostages were held, Reagan had to content himself with making grave threats -- one so ill-timed it gummed up the works of deliverance for 24 hours. But in the end, he got the hostages home, and everyone cheered.

What saved him from the fate of other politicians who say one thing and do another was that his ambivalence was shared by the country, which also wanted both to get even and to get the hostages back. Besides, nobody behaved with particular nobility. Several of the hostages emerged as apologists for their Shiite captors. Their chosen spokesman exhibited urgent indifference to the fate of their fellow victims -- the seven hostages still in captivity despite Reagan's demand they be released with the others.

Because Americans tend to confuse celebrity with heroism, the hostages have been lionized. Ironically, the one person who displayed valor -- stewardess Uli Derickson -- is in seclusion, wounded by charges that she collaborated when the hijackers ordered her to pick out passports bearing "Jewish-sounding names." It turns out she saved the life of Clinton Suggs, stopping a gunman after the murder of Robert Dean Stethem.

As for the concerted international reprisal -- Reagan's move to close down the Beirut airport -- only British Prime Minister Margaret Thatcher joined in, and only if the other Europeans do, too.

All the same, Reagan's approval rate is soaring, and in his speech to the lawyers, he showed he has found a silver lining -- the communist connection that was so maddeningly missing in the Beirut crisis.

During the 17 days of heavily televised suspense, no Red hand was visible. Now, however, Reagan has found the real culprits -- if not the murderers, at least their masters. He has fingered Iran, Libya, North Korea, Cuba and his nemesis, Nicaragua, although his evidence implicating Managua would be laughed out of court by any serious lawyer in his audience.

Nobody else has even hinted that Nicaragua was involved in recent terrorist acts. But Reagan declared that "the communist regime in Nicaragua has made itself a focal point for the terrorist network."

Moreover, he accused the Sandinistas of sponsoring terrorism in El Salvador, Costa Rica and Honduras -- "terror that led recently to the murder of four U.S. Marines, two civilians and seven Latin Americans." It was the first time anyone of consequence has linked the Nicaraguans to the recent atrocity in San Salvador. But Reagan hates Nicaragua not so much for what it has done as for what he thinks it might do, and by raising the undocumented alarm of its involvement in terrorism he might gain recruits for his limp crusade against the Sandinistas.

He wrapped up his presentation with an anticommunist bow, noting the "Soviet Union's close relationship with almost all of the terrorist states I have mentioned." That is fairly standard rhetoric from him. What was not standard was an anecdote he slipped into his closing. He told of a letter signed by 10 women prisoners in a Soviet labor camp. They told him that they, too, regard the United States as "their hope for the world."

Mikhail Gorbachev, whom Reagan is to meet in Geneva in November, may have found the reference gratuitous. But Gorbachev doesn't know that Reagan has trouble giving in. Once Reagan said he would never meet a Soviet leader without an agenda. Now he has agreed to a free-form summit.

But he had to do the right thing in the end: agree to sit down with a Soviet leader, just as he had to bring the hostages home without firing a shot. He does the right thing, and he hates himself for it. He tells anti-Soviet anecdotes, just as on the eve of the settlement with Syria he had to growl out a new warning about retribution. It's his way.