Tech executive Elon Musk cast the upcoming presidential election in dire terms during a Saturday appearance with Donald Trump, calling the Republican presidential nominee the only candidate “to preserve democracy in America.” The CEO of SpaceX and Tesla who also purchased X, Musk joined Trump in Butler, Pennsylvania, where the former president survived an assassination attempt in July. He warned “this will be the last election” if Trump doesn’t win and, clad in a black-on-black cap bearing the “Make America Great Again” slogan of Trump’s campaign, appeared to acknowledge the foreboding nature …