Defending Elections from Threats by Establishing Redlines Act of 2018 This bill requires the Office of the Director of National Intelligence (DNI), no more than 30 days after a U.S. election, to determine whether a foreign government interfered with the election and report on that determination. If the DNI reports that there was not interference and subsequently determines that there was interference, the DNI shall report on the subsequent determination. If the DNI determines that Russia interfered with an election, the President shall impose specified sanctions. The President shall brief Congress on any foreign government the President determines interfered with, or is likely to interfere with, an election.