If you think Toomey could win a Genral in PA, you really haven’t followed PA Politics. We are already about to have that idiot Al Franken from MN. That empty suit Casey beat Santorum in PA. Then we have the loons like Boxer, Leahy, Sanders and many more on the Dem. Side. Do you want to take the chance of sending another one of those to WA?
Being from Minnesota myself, I can tell you a little about the Franken/Coleman race. I personally know a number of conservatives that voted third party because Coleman was moving too far toward the middle. When you lose your base, you lose elections.
I'd expect that Santorum lost some support of diehard conservatives because of his choosing Specter over principle in 2004. Enough to lose the election? I don't know. If you think Santorum and Coleman should have moved farther to the left in order to get reelected, you're trying to lead our party (and the country) in the wrong direction, IMO.