From the Conscience of a Liberal blog on NY Times site by Paul Krugman:
[Some] are apparently uncomfortable with the notion of going after Romney the man and wish that the White House would focus solely on Romney’s policy proposals.
This is remarkably naive. I agree that the awfulness of Romney’s policy proposals is the main argument against his candidacy. But the Bain focus isn’t a diversion from that issue, it’s complementary. Given the realities of politics — and of the news media, as I’ll explain in a minute — any critique of Romney’s policies has to make use of his biography
Krugman is known more for his economics books and his money views than as a political writer, but this column is well worth reading. I am not a "vote for the man/woman not the Party" person, but for those who are, policy matters, but so does history and biography.