He could pick a governor, since he is a Senator. I don't think a military vet would be as important, now that Economic factors are more important than the Iraq War.
I think Thune could handle the economic side of the argument, and I think Iraq and Afghan will end badly along with other setbacks in middle east peace. Though, having said that, someone with military experience isn't required.
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Ridge is not pro-life, but would be a reassuring pick if terrorists strike again on U.S. soil (even in the event of an airline bombing)