The NJ tax instructions say this:
If during the entire tax
year one spouse was a resident and the other a nonresident, the resident may file
a separate New Jersey return. The
resident calculates income and exemptions as if a federal married, filing
separate return had been filed. You have the option of filing a joint return,
but in that case, your joint income would be taxed as if you both were
residents. Page 15,http://www.state.nj.us/treasury/taxation/pdf/current/1040i.pdf
