President Donald Trump's impeachment trial enters a pivotal week as his defense team resumes its case and senators face a critical vote on whether to hear witnesses or proceed directly to a vote that is widely expected to end in his acquittal. The articles of impeachment charge Trump with abuse of power and obstruction of Congress.

Two top national security aides who listened to President Donald Trump's July call with Ukraine's president are preparing to testify Tuesday at House impeachment hearings as the inquiry reaches deeper into the White House.