Despite the postponed decision, pro-NATO forces in Ukraine and Georgia celebrated the announcement, which offered stronger-than-expected support for their entry bids.
Hailing the move, Ukrainian President Viktor Yushchenko said Kyiv "has essentially broken the sound barrier."
"This can only be seen as a victory, and I will explain why," Yushchenko said. "It is because in today's document, for the first time, the 26 NATO member states formulated the basic principle that [Ukraine and Georgia] will become members of NATO. I would say this even exceeded our expectations regarding this document."
Georgian President Mikheil Saakashvili said, "I think we should be very happy," and added that it appeared as though Georgia had "suddenly jumped over the technical stage" of an action plan with the promise of full membership.
"MAP is not as important when you have a commitment to accept us as members," he said. "Here we got a 100-percent guarantee, at least formally, for membership. That's very unusual."
Before arriving at the summit, U.S. President George W. Bush said during a visit to Kyiv on April 1 that Washington wanted the two countries to move closer to the alliance.
“We support [Membership Action Plans] for Ukraine and Georgia," Bush said. "Helping Ukraine move toward NATO membership is in the interest of every member in the alliance and will help advance security and freedom in this region and around the world.”
In an interview with RFE/RL in Bucharest on Thursday evening, Czech Foreign Minister Karel Schwarzenberg said Poland had a "very important" role in securing the agreement on Georgia's and Ukraine's NATO bids.
Schwarzenberg said Germany and the United States, which went into Bucharest in strict opposition on the MAP issue, hammered out an agreement early April 3 that would have NATO foreign ministers decide on MAPs for Tbilisi and Kyiv in December.
Schwarzenberg said the original text was "not as committed to eventual membership" as the Czechs and Poles would have liked. Polish President Lech Kaczynski, however, pushed for a stronger NATO commitment to the two countries.
Kaczynski's stand, which was supported by the Czechs and the Baltic States, led to a new document that included language about NATO's commitment to eventual membership for Georgia and Ukraine.
"It was very tough" for the Germans and the French, who were strongly opposed to the MAPs, Schwarzenberg said. "But they eventually agreed."
Robin Shepherd, the head of the Europe Program at the London-based Chatham House think tank, is attending the Bucharest summit. He called the deal an "inevitable compromise."
"Everybody can walk away with something from this," he said. "The Americans have saved face because they've got a strong commitment to bring these countries into NATO, and the Europeans can save face because it didn't actually happen at the summit."
One country likely to be displeased by the development is Russia, which is a staunch critic of NATO expansion and has made no secret of its opposition to the notion of NATO moving farther into the post-Soviet neighborhood.
Russian Foreign Minister Sergei Lavrov said earlier this week that Georgia and Ukraine were "shamelessly" being pushed toward joining NATO, and he accused the United States of "infiltrating" ex-Soviet states.
Russian President Vladimir Putin, who is due to arrive in Bucharest for a meeting of the NATO-Russia Council, had threatened to skip the summit if MAPs were offered to Georgia and Ukraine.
It now remains to be seen -- possibly before the Bucharest summit ends on April 4 -- what form NATO’s further dialogue with Kyiv and Tbilisi may take.
Meanwhile, the NATO secretary-general said the alliance has decided to invite Albania and Croatia to join. But a third Balkan country, Macedonia, will have to wait a bit longer. Greece has blocked Macedonia’s entry due to a dispute over the country’s name, which Athens says implies territorial ambitions. Greece has a region named Macedonia.
Bush told the summit today that he regrets that the name dispute continues to hold up Skopje’s membership invitation.
"We regret that we were not able to reach consensus today to invite Macedonia to join the alliance," Bush said. "Macedonia has made difficult reforms at home. It is making major contributions to NATO missions abroad. The name issue needs to be resolved quickly so that Macedonia can be welcomed into NATO as soon as possible.”
A Macedonian envoy to NATO, Nikola Dimitrov, was quoted as saying NATO's rejection was "a huge disappointment" and a blow to Balkan stability. It is not yet clear what NATO may offer Macedonia as a consolation for having to wait. That, too, is only likely to become clearer in the coming hours.
"It's a terrible shame -- and I mean that word literally, it is shameful -- that Macedonia has not been invited into NATO while Albania and Croatia have," said Shepherd of Chatham House. "It is a tremendous shame that Macedonia, which has worked very hard to join NATO, which has done everything it possibly can to join NATO, has not been invited at the Bucharest summit."
The other main item on the summit agenda is Afghanistan, and how much NATO members will increase their troop commitments there.
NATO spokesman James Appathurai removed some of the suspense around that issue by saying on April 2 that France has offered “a substantial military contribution to the operation in Afghanistan.”
Appathurai said the French offer to send more troops to eastern Afghanistan frees Washington to move additional troops south to bolster Canadian forces there. He also said that move will satisfy Canada’s demands for more NATO troops in the south if it is to keep its forces in the combat area.