Mike Allen is reporting that McCain will announce his running mate on Friday, August 29 in Dayton, OH, with a second event that day featuring the running mate in Pennsylvania. He also says that Tom Ridge is out of consideration because of his views on abortion, which means that Rob Portman is the only person who makes sense regionally. If it were Romney it'd make more sense to announce in Lansing, and if it were Pawlenty Minneapolis would be a better location.
Portman's probably the best McCain could do. He's from a swing state, and from an increasingly competitive district to boot. His time as trade representative and OMB director backs McCain up on the economy, easily Mac's weakest issue area, and his 12 years in the House reinforces McCain's experience argument. At 52, he's more than young enough to run in 2012 or 2016, or to succeed were McCain to die in office. So far as I know, he has very few real negatives, either with the Republican base or with a national audience.
Which is to say, I'm pretty disappointed. A Romney VP run would have been extremely entertaining, and a Fiorina bid, in which all the sordid details of her tenure at HP are combed over by the public, would have been better still. Portman, though, isn't likely to make many headlines. He'll be a good little surrogate and not much more. Come on, McCain! There are far more amusing and disastrous choices out there. Try harder!