Provide evidence from the 1990s to the present of the conflict between the national and state government. Focus on the commerce clause.

During the last 20 years or so, there have been many
issues regarding federalism and the scope of the Commerce Clause.  The general conflict
here has been over how far the federal government may go in regulating activity that
occurs within a state while justifying those regulations through the Commerce
Clause.

One example of this was the case of
United States v. Lopez, decided in 1995.  There, the Court
invalidated a federal law that banned people from knowingly possessing guns in a school
zone.  The Court ruled that the act of possessing a gun in such a place was not
sufficiently connected to interstate commerce.  Therefore, the law was
unconstitutional.

Ten years later, in Gonzalez v.
Raich the Court came to the opposite conclusion with regard to medical
marijuana.  In that case, the Court ruled that marijuana grown for personal medical use
was still part of interstate commerce.  This allowed the federal government to override
state laws allowing medical marijuana.

Today, the fight
over "Obamacare" hinges in part on the Commerce Clause.  The Court will have to decide
whether the Commerce Clause allows the federal government to require people in the
states to buy health insurance.

These three instances show
that the interpretation of the Commerce Clause has a great deal to do with recent
conflicts between the states and the federal government.