President Trump took a swipe Tuesday at a White House official who plans to testify behind closed doors that he reported concerns about the July phone call with Ukrainian President Volodymyr Zelensky at the heart of Democrats' impeachment inquiry. Army Lt. Col. Alexander Vindman, who serves as a director on the National Security Council (NSC), is scheduled to testify before the House Intelligence, Oversight, and Foreign Affairs committees Tuesday morning. His prepared opening statement, obtained by Fox News, expresses concern over Trump's request to have Ukraine investigate political opponents, but Trump dismissed him as one of a collection of witnesses...