ON any given day of any given year, about 20 to 25 serious crises involving military force are under way somewhere in the world, says national-security expert Anthony Cordesman.
Which ones should the United States - now liberated from the Soviet threat - try to settle with its own peerless military power?
President-elect Clinton will have his own answers to that question, but President Bush has begun a legacy that Mr. Clinton is unlikely to alter radically.
Mr. Bush sent troops to feed and protect starving Somalis but not starving Sudanese. He committed massive force to save Kuwait from Iraqi aggression but not to save Bosnia-Herzegovina from Serbian aggression.
The latest move to engage US forces could come again in Iraq. The US, Britain, and their allies were reported yesterday set to warn Saddam Hussein they will take military action unless Iraq removes newly deployed missiles that threaten allied warplanes.
Bush explained to cadets at West Point on Tuesday his view of when to commit troops abroad. It was a sort of valedictory address on the subject that encompasses Bush's most celebrated triumph - the Gulf war.
But few historians or military theorists expect his presidency to leave a "Bush doctrine" for future presidents to follow.
Bush himself described a new world scene that defies formulas. "In the complex new world we are entering, there can be no single or simple set of fixed rules for using force.... Each and every case is unique," he said.
The United States would quickly exhaust itself trying to be the global policeman, Bush said: "We need not respond by ourselves to each and every outrage of violence."
But the US has both the unique ability and the responsibility to actively lead in world affairs, he said. The "entangling alliances" that George Washington warned his new country against are now essential, Bush said. "We must engage ourselves if a new world order, one more compatible with our values and congenial to our interests, is to emerge," he asserted.
As commander in chief, Bush has defined himself more in action than in words. He formed an unprecedented international coalition to stop Iraqi aggression. The military mission in Somalia, like the one to free Kuwait, is American-led but highly international and under United Nations auspices.
Broad international support through the UN is a major feature of American military commitments after the cold war. A consensus among nations is possible that was not when the US and former Soviet Union were rivals.
The legacy of the Gulf war, Mr. Cordesman says, an adjunct professor of national security policy at Georgetown University, is that the US can mobilize a multinational force to stop aggression.
A less-noted development is that the US has become more willing to intrude forcefully in the internal affairs of other countries, notes James Goodby, a fellow of the United States Institute for Peace and a former ambassador to Finland.
Most current threats to peace and democracy come from within countries, rather than from external threats. The American and international concern over these threats is often humanitarian, rather than strategic. Bush has been "highly responsive" to these new kinds of threats to humanity, Mr. Goodby says. Some recent examples:
* Operation Restore Hope in Somalia.
* Bush's threat to Serbian President Slobodan Milosevic that Serbia will face dire consequences if it attacks Kosovo, which the Serbians consider part of Serbia.
* Bush's threat of tribunals in Bosnia for war crimes.
* The no-fly zone Bush has imposed in northern Iraq to help protect Kurds.
Up to now, Bush said at West Point, he has not mobilized military action against the former Yugoslavia because it has not been clear that the use of limited force by the US and its traditional allies would be effective.
That could change, he added. "The stakes could grow. The conflict could continue to spread. Indeed, we are constantly reassessing our options and are actively consulting with others about steps that might be taken to contain the fighting, protect the humanitarian effort, and deny Serbia the fruits of aggression."
In general, says James Morrow, a senior research fellow at the Hoover Institution in Palo Alto, Calif., "the Bush administration very wisely has been reluctant to throw around American military power," because the rest of the world is very concerned about that.
"The rules have changed," says Dennis Bark, a Hoover senior fellow. "You do things in concert with other people now or you better be darn sure to have broad support." To exercise power independently is dangerous "because people resent it," he says.