NEWS ANALYSIS : A BALKAN ACCORD : Deployment May Give Clinton Political Ammo : Military: A mixture of high ambition and hard calculation went into the decision to send U.S. troops to Bosnia.

Early this month, when President Clinton told members of Congress that he plans to send U.S. troops to Bosnia, the White House meeting room erupted in protest. “There’s very little support for this in the country,” one senator warned sharply.

“I know that,” Clinton replied, according to two people present. “But public opinion is very volatile on an issue like this. It will change if the President acts. I’ve got to decide this not on the basis of what public opinion is today, but on what people are going to say 20 years from now.”

Behind Clinton’s risky decision to send U.S. troops lies a characteristic mixture of high ambition and hard political calculation--plus a new appreciation that decisive action on foreign policy can improve a President’s standing at home.

For almost three years, Clinton has pledged that the United States would send peacekeepers if Bosnia-Herzegovina’s warring Serbs, Croats and Muslims concluded a peace agreement. To back down from that commitment now--after U.S. officials helped negotiate the peace--would be unthinkable, a senior White House official said.

But the President faces a dilemma: The public doesn’t like the idea.

A Times poll in June found that a whopping 61% believed that U.S. military involvement in Bosnia was not in the national interest.

Clinton and his aides once quoted such polls as a reason for avoiding military action in the Balkans. But now that he must deliver on his promise, Clinton has told associates that he believes public opinion will move--as it has, historically, for every President who decided to send U.S. troops abroad.

Before every military conflict since World War II, when public opinion polling began, most Americans opposed sending troops into action. But as soon as the President asked for their support, they “rallied around the flag” and gave their approval, public opinion scholars said.

That is exactly what Clinton is counting on this time, probably with a formal television address. Clinton believes that he will have more luck winning support in Congress once he takes his case to the public, aides said.

“It is a given that the President will be going before the American people to make a case about the urgency of U.S. participation in helping to implement this peace,” White House Press Secretary Mike McCurry said. “The American people have questions about this. They know very little about the Balkans, but they know a lot about the horror and the bloodshed that they’ve seen for the last 3 1/2 years, and they know that the United States is in a position to do something about that.”

But Clinton’s decision to swim against the tide of public opinion also rests on another political element, some aides said. By acting decisively in Bosnia, the President believes that he can not only win support for his policy, but also increase his stature as an effective national leader.

“One of the things he has realized over the last two years is that foreign policy can help your image,” one aide said. “It makes him look like a President.”

Clinton is not sending troops to Bosnia simply to look forceful, the aides said. But “people respect a tough, straightforward decision,” one said.

It is a lesson Clinton learned a little more than a year ago, when he sent troops to Haiti despite fierce opposition--and reaped a reward in polls, one aide said. Before U.S. troops landed in Haiti in September, 1994, only 34% of the public said they would describe Clinton as “strong and decisive.”

But after a peaceful landing following negotiations that led to the departure of Haiti’s military leaders, that number increased to 40%, according to a Times poll--no landslide, but an improvement.

Clinton aides said they hope the Bosnia operation will be like Haiti: so successful and free of casualties that the public quickly forgets that the troops are there.

They fear the possibility that it might be like Somalia, the humanitarian operation that went awry in 1993, when the death of 18 U.S. troops as the result of one firefight prompted a political uproar.

“This will redound to the President’s benefit if and only if it’s a smashing success,” McCurry said. “If it’s ugly, it’s not so great.”

But while the military risks in Bosnia are clear, other White House aides and public opinion scholars said the political risks should be manageable.

“The American people aren’t opposed to sending troops overseas; they’re just opposed to taking casualties,” said John Mueller of the University of Rochester, who has long studied public opinion in wartime. “As long as there’s an exit strategy--as long as we can pull out quickly if things go wrong--the American people will be relatively forgiving.”

Times staff writer John M. Broder contributed to this report.