Yes, of course the mandate in ObamaCare is constitutional

[I]t’s worth explaining where the Constitution grants Congress the authority to impose an individual mandate. There are two short answers: the power to regulate interstate commerce and the power to tax.

First, the commerce clause. Spending on health care consumes 16 percent — and growing — of the gross domestic product. There is hardly an individual activity with greater effect on commerce than the consumption of health care…

Which brings us to the alternative source of congressional authority, the “Power to lay and collect Taxes, Duties, Imposts and Excises.”

The individual mandate is to be administered through the tax code: On their forms, taxpayers will have to submit evidence of adequate insurance or, unless they qualify for a hardship exemption, pay a penalty.