The heady "we won the Cold War" days are over. When President Obama and other NATO leaders assemble here Thursday for a key summit meeting, their No. 1 goal will be an old and familiar one: protecting vulnerable alliance members from Russia, without goading the Kremlin into military action.

After reaching out to Russia for two decades as a potential partner, NATO is once again is looking for ways to curb the Kremlin's territorial ambitions without sparking a full-scale return to expensive and risky Cold War confrontation.

But the U.S.-led alliance's eastward march into Moscow's old sphere of influence, and the demonstrated willingness of Russian President Vladimir Putin to use military might to push back when it suits Moscow's strategic goals, have created a volatile and potentially dangerous situation.

Some fear getting sucked into a spiral of moves and countermoves that in the most nightmarish of scenarios might escalate into head-on confrontation between Putin's nuclear-capable military and NATO's own forces.

On Monday, NATO announced plans for a new rapid-deployment force and the advance stockpiling of ammunition and fuel to better protect Poland and other alliance members in Eastern Europe that feel threatened by Russia.

The following day, in the latest twist of the screw, a senior Russian military official announced Moscow would be revising its own strategy to account for "changing military dangers and military threats."

For months, the U.S. and its allies have accused the Russians of blatant, ongoing military interference in eastern Ukraine on behalf of the local Russian minority, following Moscow's takeover and annexation of Ukraine's Crimean Peninsula in March.

Despite repeated Russian denials, NATO has estimated that at least 1,000 Russian soldiers have entered Ukraine, helping turn the tide in favor of pro-Russian insurgents.

Last month, the alliance's top commander in Europe, U.S. Air Force Gen. Philip Breedlove, told a German newspaper that if the Kremlin were to take similar destabilizing actions against a NATO member_in the Baltic nation of Latvia, for instance, where 27 percent of the inhabitants consider themselves Russian — it would be deemed an attack on all alliance members under Article 5 of the 1949 treaty that created NATO.

Under that pact, "the U.S is as committed to defend Riga as Berlin or Richmond," said Jorge Benitez, a senior fellow and NATO specialist at the Atlantic Council of the United States, a Washington-based think tank.

In a report issued in July, the Defense Committee of the British House of Commons said NATO is particularly vulnerable to Russia's now proven capability to wage a novel type of warfare that marshals military and non-military components including disinformation campaigns conducted over social media, fomenting civil disorder, and the use of troops operating in disguise or without identifying insignia.

A senior NATO official, speaking on condition of anonymity because he was not empowered to make public statements, said Monday that enhancing alliance capabilities to counter such "hybrid" or "assymetric" warfare is one of a package of proposals that Obama and leaders of NATO's 27 other member nations will consider at their meetings in southern Wales.

But while vowing to do more to protect frontline members of the alliance, NATO leaders appear determined to minimize the chances of provoking Putin and his generals.

One intangible that may be contributing to the cautionary mood: this year's sobering commemorations of the 100th anniversary of the outbreak of World War I, a four-year slaughter some historians contend Europe's Great Powers blithely embarked upon before thinking through the consequences of their acts.

At the Wales summit, "we will decide on measures that will further strengthen the alliance's reaction and defense capabilities," German Chancellor Angela Merkel told her country's parliament on Monday. In doing so, Merkel said it was important that NATO also uphold commitments it made in happier times to the Russians, which include a pledge to not permanently base large numbers of troops in the former Soviet sphere of influence in Eastern Europe.

The commitments are part of the NATO-Russia Founding Act of 1997, which Merkel pointedly said "is marked by the insight that security in Europe can achieved not by confrontation but only by cooperation. This is, and remains, our conviction."

In Paris, officials in President Francois Hollande's entourage who briefed reporters on France's goals for the summit said NATO must strive to deliver a "calming discourse" in the Russia-Ukraine dispute, and combine pressure on Moscow with a continued willingness to negotiate a political exit from the crisis.

The upshot, Benitez said, is that eastern NATO members won't get the permanent, large-scale alliance presence they have been demanding — or anything like the hundreds of thousands of soldiers and phalanxes of battle tanks that were deployed in West Germany to defend it from the Soviet-led Warsaw Pact.

"Diplomats and pundits will play semantics with terms like 'continuous presence,' but the bottom line is that while there will now be NATO troops conducting exercises in the eastern allies practically every day, these deployments will be short-term and smaller scale than the threatened allies feel necessary," Benitez said.

The U.S.-based analyst personally believes the alliance need a more muscular policy to check Putin's ambitions. Citing a media report of war games held recently on both sides of Russia's frontier with the alliance, Benitez asked rhetorically, "Will 6,000 NATO troops exercising in your country make you feel safe from 150,000 Russian forces exercising near your border?"

NATO officials and representatives of member countries have also made clear they think this is no time to redraw the map of Europe, because of negative effects it could have on an already unpredictable security climate. At its 2008 summit in Bucharest, Romania, then President George W. Bush and other NATO leaders agreed that Ukraine and Georgia, two former Soviet republics that the Russians consider part of their "near abroad," would one day be admitted to the alliance.

Last week, Ukrainian Prime Minister Arseniy Yatsenyuk said he would submit a bill to his nation's parliament proposing Ukraine shed its current non-aligned status and seek NATO membership. But speaking Monday to reporters, NATO Secretary General Anders Fogh Rasmussen dodged the question of precisely when Ukraine might be allowed to join, saying things were at "an early stage of the process."

A French government official flatly ruled out admitting Ukraine or Georgia at this juncture, saying "NATO, its actions, must not contribute to the tension or worsen the climate around Ukraine."


AP correspondents Geir Moulson in Berlin, Sylvie Corbet in Paris, Vladimir Isachenkov in Moscow, Jim Heintz in Kiev and Gregory Katz in London assisted in this report.