Today, the Congressional Budget Office announced the results of anew analysis of the Affordable Care Act’s individual mandate, the law’s provision that forces Americans to buy health insurance or face a fine. According to CBO, 11-12 million uninsured Americans will be subject to the mandate; the agency expects more than half of them to pay the fine instead of buying insurance. But there’s something that the CBO didn’t say: as more people pay the “tax penalty” instead of buying insurance, premiums for everyone else will go up, potentially triggering a death spiral in the private insurance market.