He may want to be Attorney General, or have a cabinate level post in the Administration as a stepping stone to the POTUS run he is expected to make in 2020 with Ryan, Rubio and a slew of other Republican up and comers.
yea, I get it, like I said in a different manner in another reply in this thread
GOP governors in Liberal northeast states have political lives that are always 100% about their own political career and none ever have or ever will build-up the GOP ranks in their own state; Christie is no different
he is campaigning out of state because it’s useful to his own political ambitions, period