This is me doing my part by passing along Scott Lemieux's passing along of Mark Schmitt's complaints about "'Miss America' compassion", since it pisses me off too. Rob Portman is one recent example, but you've also got former South Carolina Governor Mark Sanford, who's harrowing experience following the discovery of his extra-marital affair has taught him to have more compassion... for those rich people who are found to be having extra-marital affairs. To everyone else, he's the same callous bastard that he always was. Because of "principles".
The prime example for this kind of desperately limited thinking is Dick Cheney, of course, who like Portman became a passionate champion of gay rights following his daughter coming out as a lesbian, and who's also the most evil and vicious prick imaginable by any other conceivable progressive metric.
Schmitt, at the end of the day, is fairly polite and restrained here. I feel markedly less charitable. I find it impossible to give much credit at all when selfish, grasping men like Portman or Cheney start doing the right thing because it will benefit their own families. If Cheney had been shot in the face by Harry Whittington, rather than the other way round, he might have started making noises about firearm legislation, and that wouldn't have been worthy of praise either.
If Will Portman and Mary Cheney were suddenly transformed into the gay-hating straights that Michelle Bachmann insists they could be if they only tried, there's just nothing in Portman and (especially) Cheney's make-up that makes me think they'd continue to support basic human decency.
In short, prioritising one's family above one's commitment to making the world a worse place is not a principle one should have even limited appreciation for.