Sen. Ted Cruz tried to get the Senate to consider a measure Thursday providing that any American who joins the fight with terrorist groups such as the Islamic State would immediately renounce their U.S. citizenship, but a Democratic senator objected, saying more time is necessary to weigh the significant constitutional issues it raises. Ahead of the Senate’s scheduled consideration Thursday afternoon of a proposal to arm and train Syrian rebels, part of President Obama’s strategy to combat the terrorist group, the Texas Republican asked for unanimous consent to pass the Expatriate Terrorist Act he introduced earlier this month. The measure...