John McCain’s overtures that he might choose a pro-choice running mate have gone over with his party more like a lead balloon than a trial balloon many political observers assumed it was.

I told you here yesterday what a disaster such a decision would be, and Politico’s Jonathan Martin gives us concrete evidence today.

Some of the phrases used in the article include “dire consequences,“ “unenthused” and “kiss of death.“

“It would doom him in Ohio,“ one pro-life leader in the state said.

Yes, on the eve of the convention and barely 12 weeks from Election Day, it sounds like the Republican base is confident, united, fired up and ready to go!

For social conservatives, McCain’s VP pick is as much a reflection on the presidential nominee himself as it is on the one who is chosen:

For those who have been anxiously awaiting McCain’s pick as a signal of his ideological intentions, there was deep concern that their worst fears about the Arizona senator may be realized.

That is almost exactly what I wrote yesterday.

Not only would a pro-choice selection further pronounce the ideological fissure many conservatives believe exist between McCain and them, it would also seriously damage McCain’s personal credibility with his base.

A group of Ohio conservatives met privately with McCain in June, Martin reports, and while the nominee didn’t promise them an anti-abortion rights running mate, his staff said they could “almost guarantee” that would be the case.

Either “almost” means more than I thought, or “guarantee” doesn’t mean nearly what I thought.

One man who attended that meeting said he’s “not even sure [Christian conservatives] would vote for him, let alone work for him, if he picked a pro-abortion running mate.”

Again, something I said yesterday:

“Ninety percent of the workforce for Bush in ’04 came out of that constituency,” (Iowa Christian Alliance President Steve) Scheffler said, alluding to the Christian right. “Picking a Ridge or a [Joseph] Lieberman would not be helpful at all.”

If McCain picks a pro-choice running mate, the fractures in the Republican Party will make the Democratic Party’s primary issues look mild by comparison ... and the GOP will have four years to figure out how to heal them as they prepare to challenge President Obama in 2012.