The Making of Kamala Harris

Willie Brown’s protégé is remaking herself as a progressive populist.

California Senator Kamala Harris dove into the race for President on Monday, as everyone who knows her expected. Though she’s been a Senator for only two years, the victories by Barack Obama and Donald Trump have shown that ambition beats national experience as a qualification to get to the White House, if not necessarily to succeed as President.

“I love my country and this is a moment in time where I feel a sense of responsibility to fight for who we are,” Ms. Harris declared on Good Morning America. So professes every Democratic...