Although Heller is about the constitutionality of the D.C. handgun ban, the court's decision will have an impact far beyond the District.
The court must decide in Heller whether the Second Amendment secures a right for individuals to keep and bear arms or merely grants states the power to arm their militias, the National Guard. This latter view is called the "collective rights" theory.
A collective rights decision by the court would violate the contract by which Montana entered into statehood, called the Compact With the United States and archived at Article I of the Montana Constitution. When Montana and the United States entered into this bilateral contract in 1889, the U.S. approved the right to bear arms in the Montana Constitution, guaranteeing the right of "any person" to bear arms, clearly an individual right. [...]
A collective rights decision by the court in Heller would invoke an era of unilaterally revisable contracts by violating the statehood contract between the United States and Montana, and many other states.
Numerous Montana lawmakers have concurred in a resolution raising this contract-violation issue. It's posted at progunleaders.org. The United States would do well to keep its contractual promise to the states that the Second Amendment secures an individual right now as it did upon execution of the statehood contract.