Is a mandate a tax?

The health care law is currently under debate in the US Supreme Court.  At question is whether it is constitutional to impose an individual mandate to buy health insurance nationally.  I think the mandate is a perfect example of how the phrasing of logically equivalent statements can make all the difference.  In other words  “A is equal to B” and “A is not not equal to B” may both be logically equivalent but can have profound differences in the law and politics.  In the current law, everyone is obliged to have health insurance.  If they choose not to have insurance they are forced to pay a penalty.  The fact that one is compelled to engage in a commercial activity seems to be offensive to a majority of the US population.  However, congress has the right to impose a tax.  Hence, the mandate law could have been rephrased as “Everyone is assessed a health care tax and if you have health insurance, then you get a tax credit”.  This is logically equivalent to the mandate law but should have no constitutional problem since we currently pay taxes for social security and medicare.  I have never quite understood why the government doesn’t use this argument to justify the law so if anyone could explain this to me I would greatly appreciate it. It probably has more to do with the political anathema of taxation then anything else.

One last thing – there is a rationale for why a mandate is necessary, which I don’t think everyone fully appreciates.  The health care law aims to prevent people from being denied health care coverage because of pre-existing conditions.  If you make this a law then you have a free rider problem where people can simply sign up for insurance when they get sick.  This would then make insurance prohibitively expensive for everyone else.  The only way to prevent the free rider problem is to make everyone have insurance even when they are healthy and thus the mandate.  So, if you don’t want your insurance company to deny you a liver transplant because you forgot to report that you had  a broken collar-bone when you were six, then you are stuck with the mandate.  The other options are a single payer system like Canada or a fully nationalized health system like the UK but they were political nonstarters.