Rudy For Veep?

I wish that David Frum would expand on his contention that John McCain should pick Rudy Giuliani to be his running mate, beyond the argument that Rudy "shares the vision of a practical, reforming, war-winning Republican Party that inspires John McCain." I can certainly see, based on Frum's vision for conservatism and Rudy's record as New York mayor, why he signed on as an adviser to Giuliani's primary campaign. (I had hopes for the Giuliani campaign as well, once open a time.) I have a harder time seeing why he's still bullish on Rudy, after the decidedly lackluster and unimaginative campaign that Hizzoner actually ran - a campaign in which Giuliani, by Frum's own account, adopted exactly zero of his senior policy adviser's ideas for a "practical, reforming" GOP domestic agenda.