They were young lawyers, rising political stars and social acquaintances in the most exclusive quarters of San Francisco civic life. But around 2000, Kamala Harris placed a phone call to Kimberly Guilfoyle that would echo, semi-surreally, in the sufficiently semi-surreal presidential campaign of 2024. Ms. Harris was an assistant district attorney in the city. Ms. Guilfoyle was in discussions to join the office. Ms. Harris was calling, according to Ms. Guilfoyle, to suggest there was no job for her there. “She pretended to be a member of the hiring committee, which didn’t exist,” Ms. Guilfoyle said in a recent phone...