I have no doubt Rudy will find a focus group tested way to coopt some people into putting aside their principles to vote for him. I think he's the only pro-abort the GOP could nominate.
But I and many, many others, the voters (many of them independents) who will simply not vote for social liberals, the Catholics who voted Bush over 'Catholic' Kerry because of social issues, ain't gonna buy what Rudy's selling.
Look at the Pennsylvania senate race. You neutralize the social issues and all of a sudden Santorum's trailing by 15 points because the Reagan Democrats are no longer wedged into voting Republican.
Social conservatives are both the base of the GOP, and a large part of the foot soldiers who volunteer and turn out votes, and swing voters, who might be sympathetic to the Dems on other issues but vote Republican because of God, gays, guns, and abortion.
With Rudy you lose the support of both groups.
But Rudy will get make up some of that ground because he can bring in woman voters that agree with republicans on crime, taxes, defenese, ect... but do not vote for pro life republicans.