The long term prospects of the GOP in New Jersey aren't great, but Obama's margins here were almost entirely attributable to Sandy.
Yeah the Black, Asian and especially the Hispanic Population are growing while the white population stays flat so yeah demography changes in the state are not beneficial to the GOP at all plus the GOP's Hard Right Turn in the past 2 years doesn't play well here either. The House and Governor's Races are different though as opposed to the US Senate and Presidential Races in NJ.