Washington ? The imminent dispatch of 150 American soldiers to help President Eduard Shevardnadze hold his embattled Georgian nation together is a military mouse. But it threatens to become a political elephant casting shadows on U.S.-Russian cooperation in the war on global terrorism.

Russian President Vladimir Putin, who hosts President Bush in mid-May, has reluctantly swallowed the U.S. presence in the Caucasus. But the Russian military has in recent days publicly voiced suspicion of the deployment and made clear its determination to keep Georgia in Russia’s sphere of military influence whatever Putin says and whatever Bush does.

Since gaining independence through the collapse of the Soviet Union a collapse that Shevardnadze helped bring about Georgia has been shaken by plots, subversion and secession. It is about to become an important chapter in the still-unfolding story of expanding global demand for U.S. troops who once were pariahs in the developing world.

The security of much of the world suddenly balances on the shoulders of the American soldier. His (and her) presence is being solicited as a guarantor of peace in the Middle East, in Southeast Asia and most immediately along the fault lines created by the fall of the Soviet empire in Central Asia and the Caucasus. It is the time of Super GI.

Pilots, infantrymen, trainers and others have become Bush’s coin of the realm abroad as he pursues his war on terrorism. He does not shrink from the U.S. military becoming “the world’s policeman” three decades after Vietnam made that term anathema to liberals and conservatives alike. The professionalism of today’s forces, the shock of Sept. 11 and U.S. triumphs in Kuwait, the Balkans and Afghanistan have helped erase misgivings about deployment abroad.

But Americans should not become too satisfied over the welcome mat that is being rolled out so freely. The pitfalls of using military force abroad for political ends yours and others have not changed much since Napoleon warned that you can do anything with bayonets except sit on them.

Political advantage gained by military force erodes quickly unless it is backed up with long-term commitments like those made in the occupations of Germany and Japan after World War II. The GI abroad is a blunt instrument and an easy target for frustration when things go wrong, as they usually do in the kind of places U.S. troops are being sent.

The administration must be careful in choosing the wheres and whens of troop deployment. Americans must be realistic in their expectations of what those deployments can accomplish and the often-delayed costs they bring.

The Bush administration started with too modest a view of the positive change that U.S. deployment in the Balkans has accomplished. But Sept. 11 and Afghanistan will incline policy-makers to overshoot the runway in the other direction. Proposals for a U.S.-led international force to separate Israelis and Palestinians border on dangerous hubris.

One idea making the rounds at the United Nations calls for a peacekeeping force composed of U.S., Russian and European Union troops. Secretary-General Kofi Annan may advance it when he meets with American, Russian and EU representatives in Washington on May 2. The Bush administration remains properly wary.

Putin may have security architecture ideas of his own to present at his summit with Bush. “We should look at a new military alliance that would include the United States, Russia, Turkey maybe, India maybe, for Central Asia,” Mikhail Margelov, the chairman of the Russian Duma’s foreign affairs committee and a Putin ally, told me recently in Washington. “You Americans are doing in Afghanistan what we failed to do.”

But the Russian military does not seem to have reconciled itself to that rosy expansive view. A provocative two-day Russian troop deployment into the Kodori Gorge in Georgia’s breakaway Abkhazia region two weeks ago embarrassed Shevardnadze, and was followed by a declaration from Russian Deputy Defense Minister Alexander Kosovan in Moscow that an American military presence in Georgia “should worry any Russian soldier.”

The 150 U.S. soldiers due to leave for Tbilisi in early May are intended to train and equip Georgian units that will clear guerrillas out of the border region with Chechnya. The United States sees that goal as a plus for both Russia and Georgia.

But Putin has gone way out on a limb with his military and public in welcoming U.S. troops inside former Soviet borders. The deployment to Georgia gives unrepentant Cold Warriors in Moscow a heavy club to swing at Putin as the summit with Bush approaches. Super GI needs to walk carefully as well as softly in the dusty precincts where the honor of his (and her) presence is now so eagerly requested.

Jim Hoagland is a columnist for Washington Post Writers Group..