A Washington Post–ABC News poll found that 18% of voters — 33% of Clinton supporters and 1% of Trump supporters — think Trump was not the legitimate winner of the election. Sen. Lindsey Graham, R-S.C., has called on Congress to investigate the Russian cyberattack on the Democratic National Committee and the election. There are reasons for concern. According to the director of national intelligence, the leaked emails from the DNC were “intended to interfere with the U.S. election process.” The director of national intelligence, the Department of Homeland Security, and the National Security Agency concluded that the Russian government is behind the DNC email hack and that Russian hackers attacked U.S. voter registration databases. We know that the national results could be tipped by manipulating the vote count in a relatively small number of jurisdictions — a few dozen spread across a few key states. We know that the vast majority of local elections officials have limited resources to detect or defend against cyberattacks. And while pre-election polls have large uncertainties, they were consistently off. And various aspects of the preliminary results, such as a high rate of undervotes for president, have aroused suspicion.