"When did Santorum lower his britches to get his onions pruned!"
Probably right about the time he realized there will be exactly ZERO conservatives working for him in his next election. Though I'm sure a few self-styled conservatives will immediately pop up to claim otherwise.
The sad thing is I'm not even an aficionado of ID, but he did advocate it before and now he's flipping. I would rather elect a consistent, obvious lefty than a GOP waffler who'll screw you when you least expect it and need them on your side. At least with the lefty you know to keep your guard up, and at least with the lefty you will eventually get to nominate a conservative after the lefty embarrasses themselves. With guys like this, you're thinking you've got the votes, and then whammo, you get a Bowie to the dorsal.
What this more than likely means is that Santorum really isn't that bright a bulb. It shows that he's likely not reasoned any of this out himself, even less reason to support him. If he had, then he'd not have changed his position.
I know of absolutely no one that upon reviewing the evidence pro/con for both theories in an intellectually honest and objective manner that has chosen evolution for any reason whatsoever.