But the decision's ramifications could be felt in the 2016 election and beyond, especially if a Republican wins the White House next year.

That's because the Supreme Court not only ruled the federal subsidies are legal under the Affordable Care Act, but it also did not leave any ambiguity that would allow a future administration to interpret the law differently.

"The court focused definitively and said, this is what the law means," said MaryBeth Musumeci, an associate director at the Kaiser Commission on Medicaid and the Uninsured.

The challengers in the case argued the way the law was written does not allow for subsidized insurance in states where the federal government had set up insurance exchanges.