Outgoing President Donald Trump waves as he boards Marine One at the White House in Washington, D.C., on Jan. 20, 2021. (Photo by MANDEL NGAN/AFP via Getty Images) WASHINGTON - House Democrats on Thursday asked former President Donald Trump to testify under oath for his Senate impeachment trial.A Trump adviser did not immediately return a message seeking comment about the letter from House impeachment managers.The House voted 232-197 to impeach President Donald Trump, with 10 Republicans joining with Democrats to charge him with incitement of insurrection.The Senate impeachment trial starts in earnest on February 9.