Volunteers who were made to feel like top dogs, in contrast to those who were primed to recall situations of powerlessness, very quickly lost the capacity to see things from other people's perspectives. [...] Here may be another reason that the same candidates who are so exquisitely attuned to the views of others while they're desperately chasing votes become more blinkered once they're in office-and a reason that toughness can eclipse sensitivity in the front-runner in the race, regardless of gender. [...] The result, as the researchers observe, is a paradox: The very quality that often draws us to support leaders-their ability to see beyond themselves-is all too likely to fade once we've anointed them.
The paradox, though, goes away if you stop trying to find politicians who appear personally sympathetic to the plight of people in need and start trying to find politicians who are politically committed to a policy agenda that will help needy people. I have no idea whether or not there's a gap between the degree to which poverty makes John Edwards sad and the degree to which it makes Fred Thompson sad. The gap between Edwards' policy agenda and Thompson's, by contrast, is both clear and large.
Similarly, Mike Huckabee gives all indication of being a dramatically more caring human being than his GOP antagonists. He talks about the plight of the working class and seems to believe it. His record in office, though, shows a history of policies that are only very slightly heterodox. On the campaign trail, he's outlined two significant heterodox positions. One, on immigration, is something I'm pretty close to his policy views, but where his policy views are also those of the business community. His other big heterodox idea, a national retail sales tax, is stupid and incredibly regressive. And that's what you need to know.
The fact that the relevant sort of personality traits are malleable is another interesting indicator along these lines. Obtaining high political office is precisely the sort of thing that's likely to "change people" in various ways. Someone's degree of personal empathy just isn't a very good guide to anything about how they would govern.