When it is argued that it does not apply to the Anti-Injunction act.
In adjudicating the Affordable Care Act (ACA, Obamacare), Chief Justice John Roberts wrote for the majority that the Anti-Injunction Act does not apply in this case because Congress referred to it as a penalty:
The Affordable Care Act does not require that the penalty for failing to comply with the individual mandate be treated as a tax for purposes of the Anti-Injunction Act.
After deciding that the penalty for not obtaining health insurance is not a tax, the Justice in Chief decided for the majority that the penalty is a tax:
The Affordable Care Act’s requirement that certain individuals pay a financial penalty for not obtaining health insurance may reasonably be characterized as a tax. Because the Constitution permits such a tax, it is not our role to forbid it, or to pass upon its wisdom or fairness.
Justice Roberts argues that even though Congress referred to it as a “penalty”, words don’t matter when it comes to how the penalty is applied. Since the IRS will be the enforcer, and since the penalty does not involve criminal sanctions, the penalty can be considered a tax.
Now I wonder since the penalty is a tax, can someone who will be
penalized taxed by the IRS bring a case that the tax is unconstitutional because the Supreme Court called it a penalty under the Anti-Injunction Act?
I am all tied-up in knots.