Trump suggested on Sunday that he mentioned former vice president Joe Biden and his son, Hunter Biden, on a phone call with Ukrainian President Volodymyr Zelensky in July. But Trump has denied that he pressured Zelensky to investigate Biden, who is leading in polls for the 2020 Democratic presidential nomination, in exchange for military aid.
The revelations have mobilized Democrats in the House, which their party controls, with many members escalating their calls for impeachment proceedings against Trump. A trio of House committee chairs on Monday threatened to subpoena Trump for documents related to his alleged efforts to pressure Zelensky.