Lt. Gov. Gavin Newsom has amassed a war chest of more than $16 million for his 2018 bid for governor, far outpacing his rivals and cementing his position as the clear front-runner in a race that's just starting to liven up. With his dominant fundraising and consistent lead in the polls, Newsom is sailing toward the June primary as his two closest Democratic rivals, state Treasurer John Chiang and former Los Angeles Mayor Antonio Villaraigosa, struggle to close the gap and Republican candidates lag far behind. Still, Chiang and Villaraigosa have stashed away enough money to mount competitive campaigns and...