It makes good sense, until he is exposed as a Dan Quayle type. Too risky, and all for what payoff? Securing Iowa?
Vilsack will probably deliver a flattered Iowa, but since he comes from hick-land, he'll be portrayed as a golly-gee populist.
The bottom line is that Kerry has to (1) win almost all of the Gore states and either win (2a) Florida [unlikely] (2b) Ohio or (2c) both NV and NH. Ohio is the big target. In that case, I suppose Gephardt will be the obvious choice, but his union support is overrated and the union guys who always vote Democrat will continue to do so but I don't see any union-type sympathizers jumping ship just because of Dick Gephardt.