WASHINGTON — Confronting insurmountable obstacles, Majority Leader Kevin McCarthy suddenly withdrew from the contest for speaker of the U.S. House on Thursday, shocking colleagues just before they were to vote and producing ever-deeper chaos for a divided Congress. "We need a new face," McCarthy declared after a closed-door meeting where House Republicans were prepared to nominate him as speaker but instead listened in disbelief as he took himself out of the running. "If we are going to be strong, we've got to be 100 percent united."