A natural conservative who was sucked into the black hole of Manhattan liberalism and never left.
I'm not so sure that he was "sucked into" Manhattan liberalism.
He liked the good life and having a lot to see and do, so he stayed in New York.
My guess is that both his "natural conservatism" and the liberalism of his surroundings cancelled out to leave him somewhere in the middle, as would be the case if any of us really made it in the literary world.
People who say they wouldn't be corrupted or changed are often people who never had the opportunity.