Our reporters drew on court documents and dozens of interviews to explain how “Lev and Igor,” as they were known in Republican donor circles, helped Mr. Trump’s lawyer Rudy Giuliani conduct a shadow diplomacy campaign in Ukraine. It’s a tale that involves lobbyists, dinner with the president and trips to Warsaw and Kyiv.

What’s next: Mr. Trump will most likely be acquitted of the two impeachment charges approved Wednesday — abuse of power and obstruction of Congress — when he goes on trial in the Republican-controlled Senate next year. The exact timing is unclear; the House speaker, Nancy Pelosi, has said she will delay sending the impeachment articles to the Senate over concerns that its Republican majority would thwart a fair trial.

Vladimir Putin: At a marathon news conference on Thursday, the Russian president called the impeachment proceedings a baseless political ploy by Democrats, and likened them to the earlier investigation into Russian interference in the 2016 U.S. presidential election.

Closer look: Watch highlights from the impeachment voting, see Thursday’s front page of The Times and read our editorial board’s take on the Republican leaders in Congress.