I didn't say that "adult" Toomey supporters can't withhold their support from Snarlin' Arlen.
I said that Toomey couldn't do it. When he ran as a GOP candidate in this primary, IMHO he gave up the ability to run as an Independent if he lost. It just isn't done, and he would not have any chance to win statewide, heck he couldn't even win a Republican primary statewide.
It pains me to defend Specter and I really wanted Toomey to win, but we have already dodged the #1 bullet: A Specter win with the President having campaigned against him. That would have been ugly. The late surge by Toomey was a surprise to almost everyone.