Been interesting reading and listening to the various post-mortems on Romney's defeat (as opposed to Obama's victory). Romney having received roughly a million fewer votes than McCain, I have a strong suspicion that the impact of the convention shenanigans was far greater than the RE (Republican Establishment) and media ever let on and the Tea Party folks in particular weren't busting a gut to get to the polls. I really think that was the difference. Particularly when you look at how narrow the margins were in big swing states. Disenfranchising your base is not very smart politics, but then these are Republicans; maybe they overreacted to the savaging of Palin, but it was foolish just the same. You'll never catch the Democrats attempting to disenfranchise blacks or latinos at their conventions.
Which brings me to another difference between the parties. For Democrats, it's all identity politics and government benefits. For Republicans, it's all about economic politics and personal freedom.
Perhaps someday, though I doubt during my remaining lifetime, principles will again cut across racial/ethnic identity and result in elections being decided on ideas and principles rather than skin color or enforced groupthink. And I know it's not purely one or the other - but predominantly so.