Bill and Hillary Clinton, who have three Democratic presidential nominations between them, endorsed Kamala Harris for president on Sunday after President Biden halted his candidacy. “We are honored to join the President in endorsing Vice President Harris and will do whatever we can to support her,” the Clintons said in a post on X, per Axios. They said they’ve never been more worried about the nation than they are by the possibility of Donald Trump returning to the presidency. “Now is the time to support Kamala Harris and fight with everything we’ve got to elect her,” they wrote. “America’s fu…