For the first 100 days of President Trump’s new term, Kamala Harris drifted into the recesses of political defeat back home in Los Angeles. She mulled her thoughts and pondered whether to run for California governor but, noticeably, said little about the president. It wasn’t until Wednesday night that the former vice president waded back into the conversation with an affirmation of Democratic frustrations, in a speech that her camp had billed as her most extensive remarks since...