Senate Minority Leader Charles E. Schumer called Monday on President Trump’s national security team to testify before Congress about what was said before and after Mr. Trump’s meeting with Russian President Vladimir Putin. The New York Democrat called for Republicans to join with his party in demanding answers about why Mr. Trump dismissed an opportunity during the press conference in Helsinki, Finland to confront Mr. Putin about the allegation of Russia interfering with the U.S. 2016 election...