There were four separate questions before the Supreme Court in regards to Obamacare. Of those four, the issue of the individual mandate was the most controversial. Here’s a quick summary of what SCOTUS decided regarding the mandate.
Five Justices (Roberts, Kennedy, Scalia, Thomas, and Alito) rejected the government’s argument that Congress can require all Americans to purchase health insurance via its Commerce Clause power. While Chief Justice John Roberts acknowledged that Congress has wide and broad authority under the Commerce Clause, he claimed that it went beyond this authority by creating commerce where none existed previously.
However, the mandate effectively stands because a different group of five justices (Roberts, Ginsburg, Breyer, Sotomayor, and Kagan) agreed with the government’s alternative argument; namely, that the mandate and its accompanying penalty are a tax. This despite the fact that the word “tax” never appears in the law and the fact that President Obama and Democrats claimed that the law wouldn’t increase taxes.
Key quote, via Scotusblog:
Our precedent demonstrates that Congress had the power to impose the exaction in Section 5000A under the taxing power, and that Section 5000A need not be read to do more than impose a tax. This is sufficient to sustain it.
Bottom line: The mandate in Obamacare stands as a tax and the law will largely move forward. However, the ruling does apply at least some outer limit on the Commerce Clause.