In this July 10, 2018, file photo, President Donald Trump is joined by Gordon Sondland, the U.S. ambassador to the European Union, second from right, as he arrives at Melsbroek Air Base, in Brussels, Belgium. Sondland, wrapped up in a congressional impeachment inquiry, was a late convert to Trump, initially supporting another candidate in the Republican primary and once refusing to participate in a fundraiser on his behalf. (AP Photo/Pablo Martinez Monsivais, File)
WASHINGTON For only the fourth time in U.S. history, the House of Representatives has started a presidential impeachment inquiry. House committees are trying to determine if President Donald Trump violated his oath of office by asking a foreign country to investigate a political opponent.