I actually agree with Plymco and Navy that the analogy to auto insurance isn't really relevant (for the reason they noted). Note: that still doesn't make their claims of unconstitutionality correct.
We will soon see Polk as there are many efforts in progress moving in that direction. In fact with the advent of recent amendments to the bill violates the Uniformity clause in the consitution.
but all Duties, Imposts and Excises shall be uniform throughout the United States.
"
It was to cut off all undue preferences of one state over another in the regulation of subjects affecting their common interests. Unless duties, imposts, and excises were uniform, the grossest and most oppressive inequalities, vitally affecting the pursuits and employments of the people of different states, might exist" Justice Story
Further if the mandate for purchasing healthcare is found to be constitutional, then by that measure, congress will have been given a NEW power never before granted under the consitution and will be given unlimited power to legislate under the commerce clause. What seems to be lost on some is our form of Govt. is one of enumerated powers and is a limited form of Republican Government. If mandates are constitutional then that limitation is removed. As Interstate commerce will then be extended to mean human beings themselves and not the business or goods and services they engage in which the clause is actually meant to regulate. It really is a simple concept, if one chooses not to engage in the commerce, i.e. the purcahse of healthcare they are NOT engaging in the commerce and are therefor not subject to it's regulations. However, under this new meaning the person themselves are the commerce.