To comply with Iowa's new law requiring a paper trail voting systems, counties that use touch screen voting machines must either intall ATM-style printers to the machines, which show voters a printout of their choices on a continuous roll, or they can scrap the touch screens and purchase a paper ballot system, in which voters mark individual paper ballots by hand or by using an assistive device for voters with disabilities. The paper ballots are then read by an optical scanner and can be recounted by hand.

The ATM-style printers for the touch screens have come under criticism from all sides in recent years. They store votes on a continuous roll, raising voter privacy concerns, and are prone to printer jams, which can cause votes to be lost. Studies have shown that the paper trail printout is not checked by a significant number of voters, and expert security reports from Ohio and California showed that the paper roll is easily damaged either maliciously or by accident.

The user-friendliness of touch screens is also questionable. Last year members of Iowans for Voting Integrity did a study of undervotes in the statewide races on the November 2006 ballot, and found that for all the contested statewide races, counties that used only voter-marked paper ballots with optical scan had the lowest undervote, counties that used a mix of paper ballots and touch screens had the second-highest undervote, and counties that used only touch screens at the polling place had the highest undervotes. An undervote is the difference between the number of valid ballots cast in the election, and the number of votes tallied for an office.  Undervotes are considered by many voting experts to be the single most reliable measure of a voting system's effectiveness and usability. “When you see the undervote correlate with the equipment in all the contested races, you have a good idea what the best system is,” said Flaherty.  

After the state gets optical scan equipment, the next step in securing the vote is mandating random hand counted audits after the election to check electronic ballot tallies. Computer scientists who study voting systems have called strongly for routine hand audits. 17 states already plan to do audits of the November 2008 election. “You can't just have the paper; you have to use it for it to matter, “ Flaherty said.

Mauro's push for optical scan puts Iowa on the same path as a number of other states. Yesterday, Colorado Governor Bill Ritter announced an agreement with his state's lawmakers to advance legislation requiring a statewide optical scan system by November, and last week Maryland's governor announced funding for a statewide conversion from touch screens to optical scan. Florida plans to convert all polling places to optical scan by November.