That's one of the silliest contentions I've heard. Santorum is a SoCon O N L Y. And that does not make him a Conservative. Otherwise the Bush's would have been Conservatives.
If Santorum wasn’t a Conservative during his tenure, there never were any Conservative Senators ever.
http://www.redstate.com/jamesm/2012/03/11/rick-santorum-fiscal-conservative/
Rick Santorum wrote the conservative Senate version of the welfare reform law in 1995. He’s been out front on entitlement reform and supported every tax cut proposal and was always against Co2 cap-and-trade, opposed TARP, etc. Strong on immigration, and yes a so-con - so whats unconservative about being prolife profamily protaxcuts pro-less-regulation and for jobs?
It’s silly to define conservative so narrowly it excludes most conservative Republicans in office.