Their willingness to rally over the smallest perceived slight means that candidates are free to ignore the issues they care about.
Is criticism of Ann Romney going to rally the heretofore-unenthusiastic conservative base around her husband's bid for the White House? Jennifer Rubin at The Washington Post thinks so. So do two writers at TPM. And the Romney campaign's behavior suggests it too thinks it can squeeze conservative excitement from the controversy. This fleeting kerfuffle won't be remembered in a month, but that doesn't mean it won't help change the way conservatives see the election.
The fact is that ideological voters are easy to manipulate. Think of the last presidential election. Conservatives had been complaining about John McCain for years. What did it take for them to rally around the Arizona senator? A vice-presidential pick and the perception that the media was attacking her unfairly. This makes no logical sense. The media's treatment of Sarah Palin had no bearing on whether or not McCain would be a good president, or sufficiently better than Obama to justify conservatives going out to the polls for him despite their misgivings and the signal it sent about the future -- that the base is always going to rally around the Republican in the end.
But it always happens.
This year, after savaging Mitt Romney for months, some conservative Republicans are going to rally around him for reasons every bit as flimsy as a woman on CNN unfairly criticizing his wife. The GOP establishment knows it. That's why the Romney supporters among them didn't worry that by supporting the former Massachusetts governor, rather than a more conservative rival, they'd lose the base. There's always some nonsense controversy that can get the base on board. Why cater to them in candidate selection? They're often the easiest voters to rally behind the GOP.
Meanwhile, President Obama will have no problem rallying progressives, despite his atrocious record of broken promises on civil liberties and executive power, because, well, "the war on women!" Candidates hoping to win over progressives won't feel the need to keep promises on those issues in the future either. Why would they? There's always some way to remind them about their hatred of Republicans and all the very scary things that they'll do if they're given power.
It's often the case that partisans gloat when their ideological antagonists commit a gaffe on a meaningless issue. Mitt Romney says he likes firing people! Barack Obama says he'll have more flexibility after the next election! But emphasizing these tertiary gaffes is also an acknowledgement that you regard your own base as irrational enough that their vote or political donations are affected by issues of relatively miniscule importance. And that's basically true! It's no wonder that ideologues on the left and right are so routinely betrayed in the end. They're easily distracted from core issues, deeply invested in symbolic fights, and always fall in line.