On her current book tour, Hillary Clinton is still blaming the Russians (among others) for her unexpected defeat in last year's presidential election. She remains sold on a conspiracy theory that Donald Trump successfully colluded with Russian President Vladimir Putin to rig the election in Trump's favor. But allegations that a president won an election due to foreign collusion have been lodged by losers of elections throughout history. Some of the charges may have had a kernel of truth, but it has never been proven that foreign tampering changed the outcome of an election. In 2012, then-President Barack Obama...