There's been a lot of speculation whizzing around the web that this is some sort of political plot to insinuate the gay marriage issue into the currently-tight Menendez-Kean Senate race, or otherwise help tilt the playing field one way or the other.

IMHO, not so.  New Jersey's Chief Justice, Deborah Poritz, reaches the age of 70 today.  In New Jersey, all state court judges and justices are subject to mandatory retirement at age 70.  Here's a link to the official retirement announcement.  

Without getting too far into the weeds of appellate procedure, just note that this is really the last case that needs decision from the Poritz Court.  I'm guessing it will be a 4-3 split, if only because had it not been 4-3, they would not have needed to have Poritz on the Court when the decision was issued.  The short, oversimplified version of "why this is" is, for the Court to issue an opinion, the judges or justices on the Court when the case was argued must be the ones on the Court when rendering the opinion.  If the composition of the Court changes - through death, disability, retirement or otherwise - and the disposition of the case is affected by the change of personnel, then the case would have to be resubmitted, reargued, etc.  If this were a 7-0, no one would notice and the disposition would not be affected is one justice were to leave and make the decision 6-0.  

I'll speculate she wants to get this out while she's still on the Court, as a capstone to her career.

I'm also speculating that the decision will come out around and be based upon grounds in the New Jersey state constitution, and not be based upon federal constitutional grounds.  (That will have the likely, salutary effect of insulating it pretty well against one side or the other going to the US Supreme Court.)  There likely will also be a significant discussion of the statutory basis for marriage and family law, and I think I'm pretty safe speculating one side or the other will argue in their opinion along the lines of "if NJ wants gay marriage, the Legislature should enact it."

And, for those looking for a crime and politics linkage, Republican Poritz was formerly AG for Christie Todd Whitman, and not really a friend of criminal defendants.  But, she had a bit of a time moving the Court too far.  Still, she was the defendant in Doe v. Poritz, the leading case deciding that the so-called "Megan's Laws" were constitutional and not Bills of Attainder and Ex Post Facto, and spent a lot of time and effort as AG on defending those travesties.

N.B.  Before anyone gets too bent out of shape about mandatory retirement, note that in NJ judges and justices can, and frequently are, called back to work in those capacities after hitting 70.  They are technically retired, but still at work.  What the mandatory retirement age does, is open up the slots where the retired judges or justices worked for new appointees.  

2d N.B.  For those still thinking "but they're playing politics", just remember that judges in New Jersey are required, by the state constitution and court rules implementing the relevant provision, to give up all political activity (and gainful employment and other offices, too).  Truth be told, they're probably thankful that provision exists.