The U.S. Supreme Court's ruling today on the Obamacare tax credits is expected to have little impact on the Affordable Care Act.

That's because the court upheld the law's grant of tax credits to millions of Americans. The credits were intended to help people on the individual insurance market -- chiefly people who don't have insurance through work -- to afford their own policies.

For exampe, in Georgia, 90 percent of the nearly half-million people who signed up for Obamacare receive the tax credits. Many would have had to abandon their insurance had the court disallowed the tax credits.

But it didn't.

What was the ruling about?

Today's 6-3 ruling concerned an arcane point of the Affordable Care Act, which provided for the creation of online health insurance marketplaces on which individuals could shop for health insurance. These websites are known in the law as "exchanges."

The law provided for tax credits that cut the price of insurance based on the buyer's income. 

But the law specified that people would receive the tax credit when buying insurance on an exchange "established by the state." Since 37 states chose not to create their own exchange but instead used the one set up by the federal government, the plaintiffs in King v. Burwell claimed that tax credits granted to people in those states were illegal.

The court today disagreed, although Chief Justice John Roberts did note from the bench that portions of the 900-page law were sloppily drafted, according to a report on scotusblog.com.

Writing for the majority, Roberts said, "Congress passed the Affordable Care Act to improve health insurance markets, not to destroy them. If at all possible, we must interpret the Act in a way that is consistent with the former, and avoids the latter. Section 36B can fairly be read consistent with what we see as Congress’s plan, and that is the reading we adopt."

Justice Antonin Scalia, in his dissent, said the majority's decision "is of course quite absurd, and the court's 21 pages of explanation make it no less so."