DES MOINES -- Sen. Ted Cruz said here Saturday that the 2016 presidential race has entered a more serious phase following the shooting massacre in San Bernardino, Calif., and escalated his rhetoric on foreign policy with a vow to kill Islamic State terrorists."If I am elected president, we will utterly destroy ISIS," the Texas senator and Republican presidential candidate told reporters. "We won't weaken them. We won't degrade them. We will utterly destroy them. We will carpet bomb them into oblivion. We will arm the Kurds. We will do everything necessary so that every militant on the face of the...