WASHINGTON — President Bush in Kiev today will commence talks with the Ukrainian president, Viktor Yushchenko, and support expanding the NATO alliance to the borders of Russia, supporting membership bids for Georgia and the Ukraine.

The visit by Mr. Bush today carries great symbolism. It was his father, in an address that became known as the “Chicken Kiev” speech, who urged Ukrainians to remain in the Soviet Union. Today, Mr. Bush is expected to announce American support for Ukraine’s application to join the alliance that helped shatter the Soviet Union.

The national security adviser, Stephen Hadley, told reporters aboard Air Force One that the president will push hard for supporting membership action plans for both Ukraine and Georgia, two states that had successful non-violent democratic revolutions during Mr. Bush’s presidency.

“We think it’s very, very, very important that, Georgia and Ukraine, that we welcome their aspirations to be part of NATO, that we have an active engagement in helping them move in that direction,” Mr. Hadley told reporters, according to wire service accounts.

This position is bound to make Mr. Bush’s scheduled trip to the Russian Black Sea port of Sochi a dicey mission. Mr. Bush has said he will push Moscow to aid NATO’s efforts to stabilize Afghanistan. Russia’s deputy foreign minister Alexander Grushko, said on Friday that Russia would not consider helping the North Atlantic Treaty Organization in Afghanistan if the NATO alliance went forward with considering the applications from Georgia and Ukraine.

The president of the Nixon Center, Dmitri Simes, said supporting Georgia and Russia’s accession to NATO was not worth the damage it would likely inflict on the American-Russian relationship.

“What we really need most is cooperation in nonproliferation and counterterrorism from Russia,” Mr. Simes said. “If there was a Russian threat against Ukraine, against Georgia, then I would say an important principle is at stake. We cannot allow democratic nations to be bullied by Russia or conquered by Russia.” Mr. Simes said he did not think there was a military threat to either of the former Soviet provinces. Instead he said the West was defending the abstract principle that Russia should have no veto over who joins NATO.

A Russia hand who served on the Clinton administration’s National Security Council staff, James Goldgeier, said it was important for NATO not to allow Russian bullying influence its decision making, particularly in regards to Ukraine. “It’s the larger principle at stake that is important. Ukraine is a sovereign independent government. It should be able to choose whether it wants to pursue membership in NATO, and the Russians should not get a veto.”

The Clinton administration expanded NATO to include former Warsaw pact countries like Romania, the site of the NATO heads of state meeting this week. At the time, the argument to Russia, was that the alliance posed no threat to Moscow and that it was possible one day for even Moscow to join the alliance.

But the diplomacy of the 1990s was done with the government of Boris Yeltsin. The Putin government that came to power in 2000 has been more bellicose with central Asian states. Gazprom has repeatedly threatened Ukraine with cut offs of natural gas over the government’s aspiration to join NATO. Meanwhile, Russia has threatened to recognize the Georgian province of Abkhazia as retaliation for America’s recognition of an independent Kosovo. The director of the American Enterprise Institute’s Russian studies program, Leon Aron, said most of the citizens of Abkhazia now have Russian passports. Mr. Aron warned that encouraging Georgia’s membership in NATO now is “risky.” “This is a risky deal for NATO,” he said. “Once they go down that road, they cannot pull out, they will be essentially buckling under Russian pressure.”

One problem is that Russia now has peacekeepers in Abkhazia. If Georgia goes forward with NATO membership, those peacekeepers will be joined by regular Russian Army soldiers, Mr. Simes predicted. Mr. Aron said that if Georgia was an aspiring member of NATO, it could commit the alliance to taking Tblisi’s side in a war against Abkhazian secession.

The German government has said it has reservations about issuing membership action plans to Ukraine and Georgia. America and Poland have come out in favor. All member states in NATO must agree before the process is started to invite new countries into the alliance.