I thought this would be simple but it turned out my detractors were more simple.
A state can pass a law within the framework of the state constitution but can run a foul of the US Constitution but we don't know until it is challenged and finds it's way to the Supreme Court. Now Romney's bill (to be more accurate the democratic legislature's bill that Romney signed) was very specific; their definition of assault weapons which has not been challenged to the SCOTUS yet. The federal law is very much different. The SCOTUS has already confirmed that the second amendment is an individual right. The current bill is not very specific and does say handguns and shotguns so it is a general gun ban. The president took an oath to defend the Constitution and not bend it.
Stevie how long did it take you to cut and paste your comment? You article does not make it clear that it is two bills and can you show some proof that Reagan supported both? By the way, the bill passed by only two votes and the results prove that little if any benefit accrued from the ban. Both parties allowed the ban to expire in 2004. So talk to the hand.