They are expected to vote in the next few hours, on two charges against Mr. Trump: abuse of power and obstruction of Congress. A majority of House members support impeachment, largely along party lines. Here’s where every lawmaker stands.

Speaker Nancy Pelosi opened the debate with a solemn message: “He gave us no choice.” Republicans, as expected, tried to slow down the process, while President Trump mounted an indignant, all-caps defense on Twitter: “SUCH ATROCIOUS LIES BY THE RADICAL LEFT, DO NOTHING DEMOCRATS.”

Reminder: Drawing on testimony and evidence gathered during a two-month inquiry, Democrats accused Mr. Trump of misusing the power of his office when he pressured Ukraine’s president to investigate former Vice President Joe Biden.

Yesterday: Mr. Trump denounced the process as an “illegal, partisan attempted coup” in a letter to Ms. Pelosi. Read the letter, which The Times fact-checked.

What’s next: If Mr. Trump is impeached, a Senate trial will follow in the new year. With Republicans in the majority, his removal from office appears highly unlikely — though senators must take an oath to “do impartial justice.”