Gay Marriage Ruling Unconstitutional

Mickey Kaus has some good political commentary on the NJ Supreme Court's ruling. But legally, state courts and legislatures seem to have bizarre relationships. The NJ Court has ordered the legislature to write laws defining full marriage-equivalent rights for homosexuals - in 6 months. Even the most activist U.S. Supreme Court would never presume to tell Congress what laws to write. They may void a law, but never mandate one. This has happened before in NJ (for example, with school funding). Isn't this a violation of the U.S. Constitution's guarantee of republican government for each state(Article IV section 3)? How are the people supposed to respond when the deadline is sooner than it would take to amend the constitution?