Originally posted by @mott-the-hoople
what happens if you quit paying Medicare? what happens if you quit paying ACA?
Actually you're worse off if you stop paying the Medicare tax; the IRA can use its whole panoply of remedies to collect that tax, including liens and garnishments, whereas the mandate tax can only be enforced by refund intercept:
For most unpaid taxes, there are a variety of ways that the IRS can recoup their money. But the text of the ACA is very clear in stating that taxpayers who don’t pay their ACA penalty are not subject to levies, liens, or criminal prosecution.
The only way that the IRS can collect the ACA penalty is if you pay it voluntarily, or if you’re owed a refund. In the latter case, the IRS deducts the penalty from your refund. Roughly 70 percent of tax filers receive a refund, and the average refund was nearly $3,000 in 2014 and 2015.
https://www.healthinsurance.org/faqs/ive-heard-that-the-government-wont-really-be-able-to-enforce-the-penalty-for-not-having-health-insurance-is-this-true/