Read: Supreme Court opinion upholding Obamacare tax subsidies (and one feisty dissent)

The Supreme Court on Thursday upheld a major portion of the Patient Protection and Affordable Care Act, better known as Obamacare, handing President Barack Obama a major victory and reshaping how the controversial overhaul of the American health care system will factor into the 2016 presidential election.

The court ruled 6-3, with Chief Justice John Roberts writing the majority opinion, that federal tax subsidies to help the uninsured buy insurance did apply across all states, not just in those that have their own state-run purchasing systems. The decision is the second major victory for the Obama administration in the halls of the Supreme Court, after the court ruled in 2012 that the law was constitutional.

Thursday's ruling addressed the interpretation of the statute as it was written, not the law's overall validity under the Constitution. Opponents of the law pointed to the wording of the Obamacare statute, "established by the state," that taken as written could have meant the federal exchange used by many states did not qualify for subsidies. But Roberts wrote that the perhaps poor choice of words (described by some as a "drafting error") was irrelevant as Congress' intent in passing the law, making insurance available and affordable, was clear.

“A fair reading of legislation demands a fair understanding of the legislative plan," Roberts wrote. "Congress passed the Affordable Care Act to improve health insurance markets, not to destroy them."

The law's heavy presence before the court was not lost on Justice Antonin Scalia, who in summarizing his dissenting opinion from the bench said, "We should start calling this law SCOTUScare."

With the law now set in legal stone, its opponents will turn their attention to the 2016 elections in which GOP candidates will campaign in part on repealing or heavily revising Obamacare.