Donald Trump’s summit with Vladimir Putin in Alaska on Friday could be a decisive moment for both the war in Ukraine and the U.S. leader’s anomalous relationship with his Russian counterpart.

The meeting between U.S. and Russian leaders could lead to peace. But both Presidents Trump and Putin face big challenges in achieving their objectives.

Donald Trump says that within two minutes of meeting Vladimir Putin in Alaska on Friday, he will know “exactly whether or not a deal can get done” to end the war in Ukraine.