In Ohio, on his birthday, as expected. Sounds like Ridge and Liebs are out and Mitt and Pawlenty are in:

Sen. John McCain (R-Ariz.) plans to celebrate his 72nd birthday on Aug. 29 by naming his running mate at a huge rally in the battleground state of Ohio, Republican sources said…

The campaign has begun building a crowd of 10,000 for Dayton, Ohio, according to an organizer. McCain is scheduled to appear with his running mate at a large-scale event in Pennsylvania shortly thereafter.

Senior Republicans are in the dark about who he’ll name, although they say former Massachusetts Gov. Mitt Romney and Minnesota Gov. Tim Pawlenty are prime contenders after a trial balloon by McCain gave him very negative feedback about the idea of picking an abortion-rights running mate such as Tom Ridge, the former governor of Pennsylvania and the first secretary of homeland security…

McCain friends emphasized that he talks about the decision with almost no one, and could even change the announcement plans and go sooner.

As noted earlier, the timing is designed to knock Obama’s acceptance speech the night before off the front page, just like this leak to Politico is designed to at least dilute the buzz the NYT piece on Barry O’s VP pick is getting. Time to show your cards again. I say it’s Pawlenty. Predictions?

Update: For what it’s worth, a little birdie tells me Pawlenty might be otherwise engaged that day. Although schedules can, of course, can be changed last-minute to accommodate being named to a national ticket.

Update: Uh oh.

NR has learned that the McCain campaign has been calling key state GOP officials around the country the last couple of days and sounding them out about the consequences of a pro-choice VP pick. The campaign is asking about the reaction of conservative grass-roots activists to such a pick and whether a pro-choicer can be sold to them. This is an indication that the McCain campaign is serious about the possibility of a pro-choice VP nominee and that McCain leaving the door open to Tom Ridge last week may not have been merely a friendly nod to a longtime supporter.

If it’s Ridge, though, why not have the big announcement rally in Pennsylvania and then go to Ohio?