The case would be a slam dunk too. Consider if the Supremes allowed it. In such a case, a state could enact a law just like New Jersey's. Then as long as that party kept control of the governorship, they would never have to put the seat up for election- each time the special election would be coming up, the "incumbent" could resign within 30 days of the electin, allowing the governor to cancel the election and appoint a new incumbent. When the next general election would come up, that new incumbent could resign, allowing the governor to cancel the election and appoint a new incumbent. And so on, as long as they maintained control of the governorship.
If the Dems try that gambit, I would bet a lot of money Scalia, Rhenquist, O'Connor, Thomas and Kennedy at a minimum would strike that law down.