The U.S. Supreme Court has upheld the centerpiece of President Barack Obama’s signature healthcare overhaul law requiring that most Americans get insurance by 2014 or pay a financial penalty, a historic ruling that gave the White House a big win ahead of Obama’s re-election bid in November.

“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 upholding of the insurance purchase requirement, known as the “individual mandate,” was a victory for Obama on the law that aims to extend coverage to more than 30 million uninsured Americans…

The court’s ruling could figure prominently in the run-up to the November 6 election. Obama is being challenged by Republican Mitt Romney, who had called for scrapping the law and replacing it with other measures even though he championed a similar approach at the state level as Massachusetts governor…

Overdue.