President Donald Trump has often bragged about his warm relationship with Russia’s Vladimir Putin. But in the months leading up to the leaders’ first meeting in six years, Trump began asking Europeans and White House aides what’s changed about his counterpart.

Whether the U.S.-Russia summit can lead to a deal to produce peace in Ukraine more than 3 1/2 years after Moscow’s invasion remains to be seen.

For Ukraine, the risk is that Trump will push for something he’s been referring to as a “land swap.” He doesn’t say that Russia would simply get the land that it has already taken militarily, which would be problematic enough, because it would reward Moscow and Putin for invading a sovereign state.