Open Source Voting Software

I'm not particularly an open source evangelista or anything, but I read crap like this and I get to thinking that developing voting software would be an appropriate expenditure of government resources. You know, that whole 'transparent elections' thing. Turns out that there's already a group doing just that, but they don't have funding or the endorsement of any government. Why is any government, state or federal, paying for Diebold's frickin' equipment when they could have open and auditable software for the low price of $1.5 mil?