After watching Ron Paul's latest attack on Rick Santorum -- see above -- The American Prospect's Paul Waldman offers this analysis:

The attack on Santorum is actually pretty revealing. It all flies by pretty fast, but in there you have that Santorum voted to raise the debt ceiling; "doubled the size of the Department of Education" (because he voted for George W. Bush's No Child Left Behind); supported a big entitled expansion (because he voted for George W. Bush's Medicare prescription drug bill); sent billions of our tax dollars to dictators (because he supported aid to Egypt, the second-largest recipient of US aid after Israel); and gave money to Planned Parenthood (not sure, but I'm guessing it refers to something buried deep in a huge spending bill that he voted for). In other words, here's the essence of the attack: Rick Santorum was a Republican US senator when George W. Bush was president!

It just shows how far things have come in the GOP, when supporting Dubya means you weren't a real conservative.

Just to be clear, having supported "Dubya" does in fact mean that you weren't a real conservative! His hubristic attempt to remake the political culture of foreign nations via military occupation was not conservative. His profligate spending habits were not conservative. His empowerment of the federal education bureaucracy at the expense of state and local control was not conservative. His approach to immigration reform -- a guest-worker program -- wasn't conservative either. Perhaps it would be easier to respect his departures from conservative orthodoxy if he'd been a good president. As it stands, he was unprincipled and a pragmatist's nightmare. 

If the conservative movement was more grounded in substance, and less concerned with tribal and partisan loyalty, then fewer Republicans would've gone along with Bush, and the ones that did would be pariahs now, rather than contending for the GOP's presidential nomination. Instead, the candidates are just sure to never mention Bush's name, and the base is going along.