LAK,
I see you found the case on point for the "gun free" school zones law. Note that Lopez did not undo the law - it just required congress to make the interstate commerce element an element of...the offense. That's what it means to say that there is a jurisdictional element to the crime - there is some element that must be proved in order for the crime to have occurred, because the crime itself depends on a jurisdictional hook, eg, it involves an item that has traveled in interstate commerce.
Jurisdiction gets argued all the time in the Courts, which is why you have cases like Lopez and Raich. The problem is that 99 percent of the time, it is a loser, as Congress is well aware of the constitutional jurisprudence on its powers and tailors its statutes accordingly. That is why for most observers, Lopez was a surprise (and rapidly undone in effect - now Congress just targets the interstate elements more specifically in that criminal statute), and Raich was all but a foregone conclusion.
Mostly jurisdictional cases are testing the new composition of the Court, and not the actual law, which tends to be relatively predictable.
