As President Trump looked ahead this week to his high-profile, high-risk meeting with President Vladimir V. Putin of Russia, he reflected momentarily on the curious and confusing relationship between the two men. “I got along well with Putin,” he said.

Intriguingly, he used the past tense. Over the past few weeks, Mr. Trump has expressed rare frustration over the Russian leader’s unwillingness to make peace in Ukraine. But as the president elaborated earlier this week, he sounded eager to switch back to the present tense when the two sit down in Alaska on Friday.

Mr. Trump’s affinity for the iron-fisted master of the Kremlin has perplexed much of the political and diplomatic world for the past decade, challenging assumptions, fueling investigations, reshaping elections and upending alliances. Now the relationship faces its most critical test as Mr. Trump seeks to broker a halt to the war in Ukraine: Is he ready to put serious pressure on his Russian counterpart? Will Mr. Putin again win over the president to his way of thinking? Or is their friendship really on the rocks?

Subscribe to The Times to read as many articles as you like.