BUCHAREST (Reuters) - U.S. President George W. Bush sought to salvage his legacy on the world stage on Wednesday by defending the wars in Iraq and Afghanistan and appealing to Russia to drop opposition to a missile defense shield.

Laying out his agenda for his farewell NATO summit, Bush also pressed the defense alliance to put Ukraine and Georgia on the path to membership despite French and German qualms that it could further strain Moscow’s relations with the West.

Bush’s keynote speech at a pre-summit conference in Bucharest read like a laundry list of his foreign policy woes as he struggles to stay relevant abroad in the twilight of his second and final term.

But with Bush even more unpopular overseas than at home, he could have a hard time swaying world leaders as they look to whomever will succeed him as president in January 2009.

Bush is aware that NATO allies have grown weary of the war in Afghanistan against a resurgent Taliban and its al Qaeda allies but called on partners to send more troops there, saying they could not afford to lose the battle.

“Our alliance must maintain its resolve and finish the fight,” Bush said.

The issue of troop levels in Afghanistan, where some NATO allies have shied away from areas of heavy combat, has brought trans-Atlantic finger-pointing and was expected to remain a source of tension at the NATO summit starting on Wednesday.

European critics accuse Bush of being distracted by the Iraq war, which cemented his go-it-alone image.

With Iraq expected to define Bush’s presidential legacy, he kept up his defense of the five-year-old war, which has damaged credibility with friends and foes alike.

Bush said a U.S. troop buildup in Iraq had yielded significant security progress. “There’s tough fighting ahead, but the gains from the ‘surge’ we have seen are real,” he said.

But the latest increase in fighting has increased doubts of further drawdowns of U.S. forces before Bush leaves office.

APPEAL TO PUTIN

With U.S.-Russia relations deemed to have sunk to a post-Cold War low, Bush also appealed to Russian President Vladimir Putin to embrace the U.S. plan for a missile defense system partly based in Poland and the Czech Republic.

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Putin, who will be a guest at the Bucharest summit, has fiercely criticized Washington’s plan, seeing it as an encroachment on the former Soviet sphere of influence.

Bush again said the missile shield was not aimed at Moscow but was meant to deter missile threats from countries such as Iran that Washington considers dangerous.

“The Cold War is over. Russia is not our enemy,” he said.

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After the summit, Bush goes to Russia for final talks with Putin in the Black Sea resort of Sochi. Putin steps down in May.

Bush, roundly mocked by critics as naive for saying he had peered into Putin’s soul and liked what he saw when they first met in 2001, said the meeting would be the leaders’ last chance for a “heart-to-heart.”

They will try to repair relations strained over missile defense, Kosovo’s independence and NATO expansion.

Diplomats have sketched a possible trade-off, in which Moscow would accept U.S. plans to deploy its missile shield and Washington would accept a delay in NATO bids for Georgia and Ukraine, both former Soviet republics.

But Bush has denied any such deal is on the table.

U.S. officials have said the Sochi talks could yield a “strategic framework” of U.S.-Russia relations. But the meeting could also help Bush gauge how much power Putin will wield behind the scenes after Dmitry Medvedev, his protege, takes over as president. Putin is expected to become prime minister.

Aides say he Bush is now more realistic about Putin, who has become more assertive of Russia’s place in world affairs and more strident in his criticism of U.S. policies.

Bush will also have talks in Sochi with Medvedev, who won a presidential election last month after being backed by Putin.

“The president looks forward to meeting with President-elect Medvedev in Sochi,” White House spokesman Gordon Johndroe said.