If a modern Republican President started raising taxes, disarming nuclear weapons, disbanding regiments, legalising gay marriage and introducing universal healthcare the Republican base would desert him in droves. They might actually burn him in effigy.
Whereas a Democrat President can continue black-sites, embrace drone warfare and expand the war on terror to multiple countries, kill an American citizen without due process, invade the airspace of an ally and assassinate an unarmed man instead of arresting him, give the banks a free pass, actively silence whistleblowers, deport illegal immigrants, block sane drug laws, not close Guantanamo, essentially be as dodgily right wing as he wants and "liberals" will not only vote for him but ecstatically endorse him.
And these "liberals" will look down their nose at the bible-thumping conservatives and call them IRRATIONAL and TRIBALISTIC.
Because Sarah Palin. Michelle Bachmann. That's why.
Shut up