The political and legal world just got turned upside down and shaken by the ankles. The individual mandate is not valid under the Commerce Clause. Chief Justice John Roberts joined four other justices on that point. The principle of enumerated powers is preserved. But on grounds that no one thought would be taken seriously, the taxing power, Roberts sided with the liberal justices. In another surprise, the court held that the feds could not withhold Medicaid funds if states refused to expand coverage.

UPDATE (11:15 a.m.): Randy Barnett, one of the key architects of the Obamacare legal challenge, e-mails me: “Today’s decision validates our claim that a Congressional power to compel that all Americans engage in commerce was a constitutional bridge too far. By rewriting the law to make it a ‘tax,’ the Court has now thrown ObamaCare into the political process where the People will decide whether this so-called ‘tax’ will stand. And the People will also decide whether future Supreme Court nominees will pledge to enforce the Constitution’s restrictions on the power of Congress.”

The problem here, of course, is while the Obama administration swore up and down that Obamacare did not tax every American, the Supreme Court, in effect, held that the Democrats did exactly that. In that regard, the opinion is a tribute to President Obama’s utter disingenuousness.

As for the political fallout, Obama is in quite the pickle, defending a nationwide tax and a law that a majority of Americans don’t like. Mitt Romney will be able to argue that he was right insofar as the Commerce Clause doesn’t allow this extraordinary extension of power. He will also be able to fight tooth and nail against Obamatax, raising all of the policy arguments.

Conservatives will not claim the four liberal justices are stooges for the administration or declare the “fix was in.” They will take comfort in the fact that, if the feds are going to pull this stuff, they better be prepared to call their handiwork a tax. Now let’s see how many Democrats are willing to stick with Obama on this one.

UPDATE (11:00 a.m.): Showing his keen political skills, New Jersey Gov. Chris Christie gets to the heart of the matter in this statement: “I’ve been clear from the very beginning that I do not believe a one-size-fits-all health care program works for the entire country and that each governor should have the ability to make decisions about what works best for their state. Today’s Supreme Court decision is disappointing and I still believe this is the wrong approach for the people of New Jersey who should be able to make their own judgments about health care. Most importantly, the Supreme Court is confirming what we knew all along about this law – it is a tax on middle class Americans.” (Emphasis added.)

For more on the Supreme Court ruling:

Topic A: What does the decision mean?

Kathleen Parker: Winning the day with deceit

Ed Rogers: Obama won ugly, and only temporarily

Erik Wemple: CNN, Fox blow their first reaction to the health-care ruling

Stephen Stromberg: Court saves U.S. from policy pileup

Carter Eskew: Court decision gives new life to Obama

Greg Sargent: Supreme Court sides with federal power

Full text of the Supreme Court ruling

What the decision means for you