In the 1990's Republicans AGREED that the budget should be balanced, welfare ended, marriage involved one man and one woman, citizens could not be detained without due process, etc. These values were scarcely contested.
Twenty years later, the GOP has given less ground than the Dem's, but BOTH parties have drifted left.
Yeah, but only by about a half inch.
I would argue that neither party functions as a political party today...they both serve as a funnel for special interest groups (from oil and banking, to environmental foundations and gay marriage). You show up...show some money...get a Senator tied into your cause, then build onto it.