Are State Constitutions Necessary?

Tom Emmer (R-MN) has been pushing for an amendment to the Minnesota state constitution that would "allow the state government to reject any federal effort to create a universal health care program or individuals to reject any federal mandate to buy insurance" (quote taken from video summary for the below clip). Below I posted a short section of Emmer on the Washington Journal where he responds to the feasibility of a state constituion overruling a national law by asking, "are state constitutions even necessary if federal law trumps the state constitution every time?"

I personally like his first counter argument that the dissenters are "experts on the United States Constitution and...federal legal experts," which apparently means they aren't reliable sources. Also, apparently his proposed amendment has caused a bunch of 10th Amendment arguments, but I'm not sure how supporters can appeal to the 10th Amendment if federal legislation passes and establishes a national law.