STILL STANDING

WASHINGTON -- President Obama's landmark health care law remains standing today because of one Supreme Court justice's unlikely vote and for one ironic reason with huge political implications: Its key provision is a tax.

In a splintered 5-4 decision with momentous consequences for the nation's health care system, balance of government power and politics, the high court handed Obama a stunning election-year victory. Chief Justice John Roberts and the court's four liberal-leaning justices held that the law's insurance mandate represents a tax on people who do not get health coverage — a tax the Constitution gives Congress the power to impose.

Ever since three historic days of oral arguments in March revealed broad skepticism among the court's conservative justices that requiring people to buy health insurance was constitutional, the mandate looked to be in jeopardy. Shortly after 10 a.m. on Thursday inside a hushed courtroom, however, Roberts gave the mandate, the law — perhaps even the president — a new lease on life.

"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," Roberts wrote. "Because the Constitution permits such a tax, it is not our role to forbid it, or to pass upon its wisdom or fairness."

Using that logic, the chief justice saved what both sides call "Obamacare" — the most sweeping overhaul of the U.S. health care system since the creation of Medicare and Medicaid in 1965, one that presidents from Richard Nixon to Bill Clinton tried and failed to achieve.

Now it's full steam ahead for the law, which already has provided limited benefits for some seniors, young adults and people with pre-existing conditions. By January 2014, unless Congress intervenes, millions of Americans will have to obtain insurance or pay penalties, insurers will be banned from denying coverage based on pre-existing conditions, states will have to decide whether to expand Medicaid and create new insurance exchanges where people can shop for affordable coverage, and many small businesses will have to cover workers with the help of tax credits or pay penalties.

With a 59-page stroke of his pen, Roberts — a George W. Bush nominee whose 2005 confirmation as chief justice was opposed by one Sen. Barack Obama— sided with the court's four liberal justices in upholding the most consequential and controversial piece of legislation enacted during Obama's presidency.

The law now "survives largely unscathed," said Justice Ruth Bader Ginsburg, who like most justices on the court was unhappy about some part of the decision. Four justices, in fact — just one short of a majority — would have struck down the entire law, jeopardizing provisions that are already benefiting young adults, seniors and others.

"The Affordable Care Act now must operate as the court has revised it, not as Congress designed it," lamented Justice Anthony Kennedy on behalf of himself and Justices Antonin Scalia, Clarence Thomas and Samuel Alito. He called it "a vast judicial overreaching."