The United States isn’t ready to hold elections online now or in the foreseeable future, a new report says. Not until the technology is good enough to ensure the votes are kept private and aren’t tampered with.

The recommendation is part of a massive new National Academies of Sciences, Engineering, and Medicine report that lays out dozens of recommendations for an election system the report calls “accessible, reliable, verifiable, and secure.” A big one is to phase out voting machines that don’t leave a paper trail, and only use paper ballots that humans can double-check — ideally by the 2018 midterm elections, but for sure by the presidential election in 2020.

“The most significant threat to the American elections system was coming ... from efforts to undermine the credibility of election results.”

Among the other recommendations, the report says that states should require something called “risk-limiting audits,” where a selection of ballots are checked to make sure that election results make statistical sense. Election officials and vendors should keep a close eye on registration systems and report any tampering.

The committee that authored the report was co-chaired by Lee Bollinger, president of Columbia University, and Michael McRobbie, president of Indiana University. In the preface, they write that back in the fall of 2016, they thought they’d be dealing with issues like interminable lines at the polls and evaluating new technology. “We suspected that we would find that voting systems are moving away from in-person physical balloting toward systems that embrace technologies that enable remote (Internet) voting,” Bollinger and McRobbie write.

Then the 2016 election happened, and “America’s election infrastructure was targeted by a foreign government,” the report says. Now, the committee is recommending moving in the exact opposite direction: going back to paper ballots that can be double-checked, and shoring up our election infrastructure against cyber incursions. Bollinger and McRobbie write: “It was clear that the most significant threat to the American elections system was coming, not from faulty or outdated technologies, but from efforts to undermine the credibility of election results.”