For the second time in three years, Ukraine, the former Soviet republic between Russia and the West, has been caught in the glare of American news cameras because of an American political drama. In 2016, the spotlight was trained on the campaign chairman for Donald J. Trump, then the Republican candidate for president, and the aide’s undisclosed business with a pro-Russia political party.

This year, the cameras are directed at President Trump and his dealings with Ukraine’s new president, a former comedian who played a teacher-turned-president on TV.

How did Ukraine get here?