MOST voters yearn for closure after an unusually bitter election campaign, but three of the four candidates for the presidency now claim that the election may not have been free and fair. The loudest is Donald Trump. The president-elect frequently alleged that the election process was rigged and voter fraud common in the run-up to the election. On November 27th he tweeted that he had won the popular vote, “if you deduct the millions of people who voted illegally.” Jill Stein, the Green Party’s candidate, raised millions of dollars for a recount of votes in Wisconsin, Pennsylvania and Michigan, where Mr Trump’s margins of victory were thin. And after initial hesitations, Hillary Clinton’s campaign joined the drive for a recount in the three Midwestern states which, together, handed Mr Trump his victory.

Ms Stein denies that she is pushing for a recount to overturn the election result. She says she is spurred by worries about the “hackability” of voting systems in the wake of the hacking of the Democratic National Committee’s network, voter-registration databases in Illinois and Arizona and the e-mail account of John Podesta, Mrs Clinton’s campaign manager. Some suspect that Ms Stein is partly driven by the publicity generated by her initiative and the inflow of funds (and donors’ contact details) to finance the recount. The initiative has given her more airtime than ever before and brought in about $7m, more than she received in the whole year for her presidential run.

Recounts are unlikely to overturn the result. The election was decided, in effect, by slightly more than 100,000 people in three Midwestern states. Mr Trump won Wisconsin with a margin of 0.8% (or 22,000 votes), Michigan with a margin of 0.2% (11,000 votes) and Pennsylvania with 71,000 votes, a margin of 1.2%. But these margins are bigger than any overturned before in a recount.

Merle King, of the Centre for Election Systems at Kennesaw State University, argues that the hacking incidents during the campaign do not mean that voting systems can easily be infiltrated. Voting technology differs between states and even county by county, with some counties using paper ballots, others paperless technology, making a large-scale hack very tricky. Around 75% of all votes are cast on paper, which is safer than those cast on electronic voting machines, some of which provide no paper trail as backup and can be hacked, as researchers have shown. Nearly all states use federally certified technologies, such as encrypting results several times before they are transmitted to a central repository.

Philip Stark, a statistician at the University of California, Berkeley argues that elections never work perfectly because of human error. Recounts usually produce a different result. Ballots can be torn when they are put through a scanner and a sensitive scanner can count a mark where a pencil just rested as a vote. The goal, says Mr King, is to get a reasonable approximation of the result.

The recounters are on a tight deadline: the electoral college must do its work by December 13th. However costly and tiresome, argue Mr Stark and Ronald Rivest of the Massachusetts Institute of Technology, elections should be audited regularly, not only when margins are slim. If the results are confirmed, they will bolster voters’ belief in the system. If the process goes badly, as was the case with the chaotic recount in Florida after the presidential election in 2000, it will trigger reforms, such as the famous banishment of hanging chads (partly-punched paper cards). Either way, voters will be able to move on.