This is true because Christie is perhaps the only possible challenger who can a). match Obama in terms of charisma and gravitas, but b). do so in a completely different manner.
Both these elements are important. The sooner Republicans realize this, the better. Unfortunately, several plausible, but misleading arguments have sprung up to muddy the waters…
An equally flawed theory is the notion that the best way to beat Obama is to find our own Obama (the people advancing this notion mean that Republicans should run someone who is philosophically conservative, but stylistically similar to Obama).
This, too, is a flawed theory; campaigns are about contrast not similarity. If you like thin, professorial types — you’re probably voting for Obama in 2012. You’re not going to out-Obama, Obama. (Note: In 2016, a conservative Obama might work — but not in 2012). In this regard, how could you find someone more stylistically different from Obama than Chris Christie?