The U.S. Supreme court ruled Thursday to uphold the controversial health care law proposed by President Barack Obama.

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, Chief Justice John Roberts wrote for the court's majority.

Because the Constitution permits such a tax, it is not our role to forbid it, or to pass upon its wisdom or fairness, he concluded. The conservative Roberts joined the four most liberal justices to uphold the law's key provision.

The four dissenters, all from the court's conservative wing, were Justices Antonin Scalia, Anthony Kennedy, Clarence Thomas and Samuel Alito. They would have struck down the entire law.

The Affordable Health Care Act is supported by the tax clause of the U.S. Constitution, the Supreme Court held, not the Commerce clause, which the Obama administration had argued before the Court, CNN reported.

The 5-4 ruling by the high court mandates not only a requirement to have valid health insurance, but it is also a huge victory for the Obama administration.

Just two hours after the historic decision, President Obama began speaking live from the White House at 12:15 p.m.

The White House will live stream Obama's comments on this momentous supreme court ruling.