Russia's blitz into the former Soviet republic of Georgia has exposed starkly the limits of US military power and geopolitical influence in the era following the invasion of Iraq.

Georgia is one of the closest US allies in Eastern Europe. President Mikheil Saakashvili has visited the White House three times in the last four years. Yet this warm relationship did not stop the Kremlin from unleashing a ferocious military response after Georgian troops entered the separatist province of South Ossetia.

US efforts to expand Western influence and spread democracy along Russia's borders may now be threatened. US relations with Russia itself, at the least, are in flux.

"This gets at the stability of the framework the US thought was going to govern the post-cold-war world," says Stephen Sestanovich, senior fellow for Russian and Eurasian Studies at the Council on Foreign Relations.

Russian leaders on Tuesday said they had ordered a halt to military action in Georgia. The move followed five days of air and land attacks that had routed Georgia's Army and sent Russian troops deep into Georgian territory.

Russian President Dmitry Medvedev announced on national television that Georgia had been punished enough for its move against South Ossetia, which has close ties to Russia. But Medvedev did not immediately announce any withdrawal of forces from current positions and there were reports of continued scattered fighting.

"If there are any emerging hotbeds of resistance or any aggressive actions, you should take steps to destroy them," he told his defense minister at a televised Kremlin meeting.

President Bush, for his part, on Aug. 11 demanded that Russia end its dramatic escalation of violence in Georgia and agree to an immediate cease-fire and international mediation.

"Russia has invaded a sovereign neighboring state and threatens a democratic government elected by its people. Such an action is unacceptable in the 21st century," said Mr. Bush in a statement televised shortly after his return to the US from the Beijing Olympics.

But since the crisis began, there has been no hint that the United States would consider any kind of military move, even logistical aid for Georgian forces, that would bring it into direct conflict with Russia. The US and the West appear to have little leverage over a Moscow that is flush with oil money and eager to reestablish its position along its borders.

Expulsion of Russia from the G-8 group of industrialized nations was among the few apparent strong actions the US and Europe could take.

Other possible moves include threatening Russia with the loss of the 2014 Winter Olympic games at the Black Sea resort of Sochi.

"The United States, its allies, and other countries need to send a strong signal to Moscow that creating 19th-century-style spheres of influence and redrawing the borders of the former Soviet Union is a danger to world peace," said Ariel Cohen, senior research fellow in Russian and Eurasian studies at the Heritage Foundation, in an analysis of the impact of the crisis.

Georgian President Saakashvili has long been one of the Bush administration's favorite world leaders. Georgia contributed 2,000 troops to the US effort in Iraq, and Mr. Saakashvili has talked often of his support for Bush administration efforts to spread freedom and democracy among the countries of the former Soviet Union.

Saakashvili and Bush seem to share a good personal chemistry. Bush visited Georgia in 2005; during Saakashvili's return visits to the White House, the two joshed about folk dancing and their wives' luncheon plans.

In March, at a White House appearance, Saakashvili thanked Bush for supporting Georgia's aspirations to join NATO and for "protecting Georgia's borders."

"I think this is a very unequivocal support we're getting from you," the Georgian leader told the US president, for the cameras.

The US has long publicly stated that it is in favor of a peaceful settlement of Georgia's disputes with its breakaway provinces of South Ossetia and Abkhazia. Yet Saakashvili decided to send troops into South Ossetia, anyway. That appears to have been the spark that set off the crisis – or the provocation that Russia was waiting for.

Perhaps the Georgian leader thought the US would come to his aid if he got in trouble. If so, he did not take into account the drain that Iraq has been on US forces and the US standing in the world – or the American need to work with Russia on other important geopolitical issues, such as the effort to curb Iran's nuclear program.

"In many respects, Saakashvili got too close to the US, and the US got too close to Saakashvili.... Perhaps that made him overreach," says Charles Kupchan, senior fellow for Europe Studies at the Council on Foreign Relations.

Ukraine, among other nations, will surely watch the outcome of this crisis closely, according to Mr. Kupchan. US hopes of girdling Russia with Western-oriented governments now appear in question, as Moscow reasserts influence over its "near abroad."

US hopes that Russia would be essentially a benign economic partner may also have been dashed when Russian tanks rolled into Georgian territory.

"Victory in this war with no consequences for Russia will reinforce antidemocratic forces in Russia, increase the militarization of its foreign policy, and encourage Russia to take more risks elsewhere on its borders," says Stephen Jones, professor of Russian and Eurasian studies at Mount Holyoke College in South Hadley, Mass.

With the US far from the area of conflict, European attitudes will be crucial. Yet on Georgia and Russia, different European countries take different positions, and they have serious internal disagreements as well.

The European position tends to skew along lines of interest and history. Older European states, such as France and Germany, have strong economic and energy ties to Russia and see themselves as necessarily working with Moscow. Former Warsaw Pact states like Poland, Hungary, and the Baltic nations view Moscow with real suspicion based on bitter recent history as involuntary allies of the Soviet Union.

Britain, increasingly wary of Prime Minister Vladimir Putin's Russia, takes a dim view of Moscow after a season of tensions and spats. East German-born Angela Merkel, Germany's chancellor, regards Prime Minister Putin at least as a question mark, but she has been skillful at pragmatic moves that have kept Berlin-Moscow relations strong.

"Nothing meaningful can be done as a matter of American policy if there is no consensus among European states that this represents something deeply shocking," says Mr. Sestanovich of the Council on Foreign Relations.

• Robert Marquand in Paris contributed to this report. Material from Associated Press was also used.