Trump is hinting at concessions to Putin. So what do we get back?

"We really believed in our hearts that this was the dawn of the new day we had all been praying for," Harry Hopkins told his biographer. "We were absolutely certain that we had won the first great victory of peace." Hopkins, one of President Franklin D. Roosevelt's most important advisers, was not the only one present to have considered the Yalta Conference in February 1945 a great success. In his book on Yalta, the Harvard scholar Serhii Plokhy points out that everybody in the U.S. and British delegations, from gloomy George Kennan to cautious Winston Churchill, was pleased with the result. Britain, the United States and the Soviet Union seemed to have settled their differences, sketched out their spheres of influence and agreed that after the German capitulation, the liberated countries of Europe should all be democracies.

The good cheer was brief. Within a few months, American and Soviet soldiers were shooting at one another over armistice lines in Bavaria. The false Soviet promise to bring democracy to liberated Eastern Europe degenerated almost immediately into farce. The "victory of peace" turned into the beginning of the Cold War, a generation-long struggle that involved an arms race, a massive American troop presence in Europe and the oppression of half the continent.

Keep this history of the Yalta treaty in mind over the next few days, as the White House prepares itself for the first summit of President Donald Trump and Vladimir Putin. Of course there are some differences. This is not 1945, and nobody believes this is "the dawn of a new day": It is a strange meeting between the Russian president, a kleptocrat, and the American president, his longtime admirer.

But the expression "new Yalta" has been kicking around ever since this administration arrived in Washington. It's an idea the Russians like enormously, because it implies that they are once again a superpower, once again America's equal, once again sitting down at the table to divide up the world. For Putin, it's a key part of his domestic strategy: As a leader without the legitimacy conferred by democracy, he needs to constantly prove to his countrymen that he deserves to rule. For the United States, the advantages are much murkier. Rumors of what kind of deal might be on the table are proliferating nevertheless.

Some of them involve Ukraine. Trump and his national security adviser have both hinted that recognition of the Russian occupation of Crimea is on the table; Trump even repeats Russian propaganda about Crimea's ethnicity and politics. Another was laid out in The Washington Post by David Ignatius a few days ago: Trump may be planning to cede Syria to Putin, abandon U.S. allies on the ground and allow Russia's client, the dictator, Bashar Assad, to reestablish control across the country, inflicting massive civilian casualties along the way.

In neither case is it clear what the United States would get in exchange for these major concessions. One version says Putin would promise to withdraw the Russian troops whose presence he denies from eastern Ukraine. Another says Putin would promise, somehow, to contain Iran, a country with which, in Syria, he is allied. Talk of this latter deal dates to the earliest days of the administration, back when Jared Kushner, all those months ago, sought a secret channel of communication with the Russian government.

But all these deals, just like the original Yalta agreement, have at their heart a fatal flaw: They rely on promises from a Russian leader who has never, in Syria, Ukraine or anywhere else, kept his word. In Ukraine he has continued to bankroll the "rebels" who continue to prosecute an illegal war in the east. In Syria he has repeatedly reneged on commitments to lift sieges, allow the delivery of humanitarian aid and deescalate conflict, yet he has paid no price. Even if he wanted to, the idea that he can somehow control Iran is peculiar: The Russian foreign minister has already said that it is "absolutely unrealistic" to expect Iran to remove itself from the conflict. The Russian military doesn't have the troops for that anyway.

In both Ukraine and Syria, the situation is extremely odd: The United States - still, in theory, the stronger power - appears to be negotiating to give up quite a lot in exchange for very little. The only explanation for U.S. determination to make a lopsided deal is Trump himself. Perhaps he has learned from his experience negotiating with North Korea: In Singapore he endorsed a dictator, got nothing except unenforceable promises and then came home to a hero's welcome from Fox News. Or perhaps he still feels he owes something, after all, to the man who helped him win the presidency.