A House investigatory panel has summoned Democratic presidential candidate Hillary Clinton to testify at a May 18 public hearing about her use of a private email server during her tenure as secretary of state. The panel, which is probing the September 2012 terrorist attacks on the U.S. Consulate in Benghazi, Libya, has scheduled a second public hearing one month later, on June 18, to grill Clinton about Benghazi. Both hearings are contingent upon Clinton providing "a complete record" about her role before, during and after the attacks, which killed U.S. Ambassador Chris Stevens and three other Americans. That may be...