President Donald Trump’s inability to find peace in Ukraine — a war he once claimed would be over the day he took office — has caused him enormous frustration. But the focus of his ire has zig-zagged throughout his second term in office.

At moments, Trump has flashed anger toward Ukrainian President Volodomyr Zelensky, casting him as ungrateful and unwilling to compromise.

Other times, he has vented about Russian President Vladimir Putin, who he once hoped would agree to a peace deal because of their close relationship.

Tracking the back-and-forth has become a pastime for European officials, who have worked to keep Trump on Ukraine’s side, even as he sometimes parrots Russian talking points.

Who Trump appears to favor often reflects who he spoke with last. Trump will have a face-to-face meeting with Zelensky on the sidelines of a NATO summit in Turkey on Wednesday.

But he also spent more than an hour on the telephone this weekend with Putin.