The original idea behind regulating interstate commerce was to make commerce regular, meaning that the federal government could stop interstate protectionism. The founders didn't believe the federal government should have a vested interest in the commerce only that they should have the power to stop one state from enacting tariffs on other states. That along with not being given the power to regulate intrastate commerce in any way shape or form, and being explicitly denied the right to regulate firearms at all, means that Montana is absolutely within their right to nullify the federal government's law.
Legislative intent is not the sole deciding factor though.
If we do not go with original intent then we are committing fraud. The states ratified the Constitution with certain understandings of how it was going to be interpreted, and to change the meaning after the fact is fraud.
No, sorry.
First, fraud was more narrowly defined during the days of the creation of the Constitution. And your assertion would of fraud would thus fail.......going by your logic.