A few countries, like Estonia, have gone for internet-based voting in national elections in a big way, and many others (like Ireland and Canada) have experimented with it. For Americans, with a presidential election approaching later this year, it’s a timely issue: already, some states have come to allow at least certain forms of voting by internet. Proponents say online elections have compelling upsides, chief among them ease of participation. People who might not otherwise vote — in particular military personnel stationed abroad, but many others besides — are more and more reached by internet access. Online voting offers a way to keep the electoral process open to them. With online voting, too, there’s no worry about conventional absentee ballots being lost or delayed in the postal system, either before reaching the voter or on the way back to be counted. The downsides, though, are daunting. According to RSA panelists David Jefferson and J. Alex Halderman, in fact, they’re overwhelming. Speaking Thursday afternoon, the two laid out their case against e-voting.