KEY POINTS:
PARIS - The monstrous palace built for Nicolae Ceausescu in Bucharest provides a grimly historic backdrop for Nato leaders this week as they sketch the alliance's future.
A blockhouse of 1000 rooms and 4500 chandeliers, the parliamentary building is a symbol of the Soviet era, when the hallmark
sentiments were the West's fear of Russia and Moscow's suspicions of Nato.
The same emotional undercurrents will swirl around the two-day summit of the 26-nation Atlantic alliance on Thursday and Friday, followed on Saturday by the participation of Russian President Vladimir Putin.
The meeting has a tang of Nato summits 20 years ago, when the big issue then was how to counter the Soviet short-range nuclear threat to Western Europe.
Internally, the trick for Nato was how to balance the United States' instinct for a tough response with divisions among Europeans fearful of provoking the Soviet Union. Externally, the challenge was to reassure Moscow that Nato's aims were purely defensive and should not be considered a threat.
The same tightrope walk is required in Bucharest, where leaders must decide how far Nato should dangle military membership to Ukraine and Georgia, a move that Moscow sternly warned last week would be "extremely troublesome" for European security.
"No state can be pleased about having representatives of a military bloc to which it does not belong coming close to its borders," Putin's successor, Dmitry Medvedev, said.
The US is leading the push for the two former Soviet republics to join Nato's so-called Membership Action Plan (Map), a stepping stone to full alliance membership.
The US position is backed by nine ex-communist Nato members as well as Canada, but opposed by eight countries in continental western Europe, diplomats in Brussels say.
Germany - the only country to go public with its objections - says that in Ukraine, a large, pro-Moscow part of the population opposes the path of Nato membership taken by its pro-Western leaders. This problem has to be resolved before the alliance's doors can be opened, it argues.
As for Georgia, membership could stoke regional instability, a codeword for the country's two breakaway regions, Abkhazia and South Ossetia, Germany says.
Georgia accuses Russia of stirring up separatism in both regions and last week sent its Foreign Minister to Nato headquarters to beg members not to yield to "appeasement" of Moscow.
Behind the scenes, European countries fret about fuelling tensions with Russia, a vital energy supplier to Europe, just as the newly-elected Medvedev is about to take office.
Relations between Nato and Moscow have already been badly strained by US plans to install components of an anti-missile shield in central Europe, a scheme that Washington says aims at thwarting Iran, not Russia.
And some Europeans also suspect President George W. Bush is belatedly driving hard for Ukrainian and Georgian membership to provide a legacy of his time in office. Bush is due to fly to Kiev, the Ukrainian capital, on the eve of the summit.
Croatia and Albania are likely to be offered formal membership at Bucharest, as well as Macedonia, provided a row with Greece over the country's name can be fixed.
But resolving the wrangle over Ukraine and Georgia will be far tougher and likely to result in a textual balancing act. All 26 nations agree "it is not a question of if [on Map] but when, but this doesn't change the fact you need all of them" for agreement under the rules of unanimity, a Nato diplomat said.
The summit's other big headache is Afghanistan.
European members of Nato are under intensifying pressure from the United States, Canada and Britain to beef up their contributions to the Nato-led International Security Assistance Force (ISAF) there.
The summit's second day - which will be attended by Afghan President Hamid Karzai, the UN and representatives from the 39 ISAF nations - will essentially be a pledging session and a review of the alliance's biggest military operation.
French President Nicolas Sarkozy last week said his country would increase its military presence in Afghanistan, where it currently has some 1600 troops, on condition that Afghans are given more responsibility and an improvement in the non-military aspects of the mission.
Press reports in Paris say the additions number 1000. Poland last year promised an extra 400 troops.
But ISAF's commanders are calling for between 6000 and 10,000 troops, focused on the dangerous south of the country to cope with the Taleban.
