UPDATED*: It appears that the Affordable Care Act, otherwise known as “Obamacare” has been upheld by the US Supreme Court. The expansion of Medicaid by the federal government has been allowed, but states do not have to participate. The majority opinion, as read by Justice John Roberts, states:

“Nothing in our opinion precludes Congress from offering funds under the ACA to expand the availability of health care, and requiring that states accepting such funds comply with the conditions on their use. What Congress is not free to do is to penalize States that choose not to participate in that new program by taking away their existing Medicaid funding.”

This means that is some states, for example Florida, Texas and other big states choose not to participate, then there will be millions of Americans who will miss out on the benefits of the healthcare reforms.

The Scotus Blog provides this very useful summary:

“In Plain English: The Affordable Care Act, including its individual mandate that virtually all Americans buy health insurance, is constitutional. There were not five votes to uphold it on the ground that Congress could use its power to regulate commerce between the states to require everyone to buy health insurance. However, five Justices agreed that the penalty that someone must pay if he refuses to buy insurance is a kind of tax that Congress can impose using its taxing power. That is all that matters. Because the mandate survives, the Court did not need to decide what other parts of the statute were constitutional, except for a provision that required states to comply with new eligibility requirements for Medicaid or risk losing their funding. On that question, the Court held that the provision is constitutional as long as states would only lose new funds if they didn’t comply with the new requirements, rather than all of their funding”

You can access the opinion here.

* There are also good summaries of the decision here and here