The main arguments where similar to the people being bearish on Christie's chances, namely past moderation on social issues and support for the policy model for Obamacare. But in hindsight this is pretty silly. Romney was able to deal with abortion just by flip flopping and embracing Republican boilerplate language. And while Ross Douthat may acknowledge that Romneycare really did pave the way for Obamacare when he lies awake in the deep hours of night, it didn't actually turn out to be that much of a liability. Policy is complicated and most people, even committed partisans don't pay that much attention to it. The same thing happened in 2008 when Obama was seen as the more "liberal" or "progressive" candidate compared to Clinton when on policy stances it really didn't appear that way.
As I put it in the pieace:
Christie can get around his past stances as long as he is willing to adopt the current party line while running for President. Rand Paul calling for a foreign policy of isolationism means he can be vetoed by power groups inside the Republican Party. But as long as Christie is willing to change his stances and prove his loyalty over the next few years by saying “he evolved” on issues (like Obama and same sex marriage), he should be fine.Anyway, you should check it out and like it on the facebooks or whatever.
As long as Christie doesn’t lose next month or completely fail as Governor over the next two years he will clearly meet the convention qualification to be the GOP’s nominee. And as long as Christie doesn’t become an outspoken advocate of abortion rights or another Democratic position he is very much inside the socially moderate and pro-business “country club” tradition of the Republican Party.