The NJ Supreme Court decision affected the ballot that would appear on election day, making it subject to Federal regulation.
Further, the decision was that of the NJ Court and not the State Legislature, which is also in violation of Article 1, Section 4.
Your arguments have taken every power out of the hands of the states why not one more? When will it be enough? Was the decision made by the NJ SC correct? No, it was not. However this is an issue for the state courts. In the long run, this decision works towards the rights of the states and how they run their internal affairs, something I thought conservatives still cared about