Here is a frightening prospect: with four weeks to go before Election Day, some of America’s voting machines are not as secure as they could be. For years, the idea that hackers might mess with a U.S. election seemed more like the plot of a novel than a real possibility. As a result, election administrators have tried to save taxpayer money by using the same machines year after year, even after vulnerabilities with some voting machines were exposed. This year is different. Cyber attackers in Russia have targeted U.S. election systems, taking aim at the Democratic National Committee and voter registration databases of more than 20 states. The risk is small, but real. Let’s start with good news: you can trust the national outcome. Most Americans vote on paper ballots. Those ballots are mainly counted by efficient, accurate optical scan voting machines, and, in most states, they are also audited — hand-counted in public in a small number of randomly selected precincts — to make sure that the optical scan machines are working right. If the election is close enough to merit a recount, or if a random audit shows an anomaly, more precincts can be counted by hand.