Nominating socially liberal Republicans hurts the interests of social conservatives. Any other claim is pretense. The Republican party should never nominate anyone who isn't conservative on social issues in specific.
The party platform is quite socially conservative. We can just stick with that as our metric for what kind of candidates we should support. That's why I made my chart a while back that shows where Giuliani stands in comparison to the platform. The Republican Party should never nominate anyone who isn't mostly consistant with its own platform. Giuliani isn't even close.