Does Voting Technology Affect Election Outcomes?
Economists David Card and Enrico Moretti have just published a working paper that analyzes correlations between voting technologies and electoral outcomes.
Short story: when people could, they tended to touch W, and touching tended to depress turnout (especially in districts with larger ratios of Hispanic voters). Somehow, this did not seem to reflect fraud, since the affected counties did not seem strategically "important."
I'm still not bubbling over with confidence.