President Barack Obama signed the Patient Protection and Affordable Care Act four years and four months ago. Yet debate over the law persists - and federal judges are among those expressing such differences of opinion.

Two opposing rulings by federal appeals court panels vividly reconfirmed that ongoing conflict Tuesday. And while confusion continues over what Obamacare means, this much is clear: The landmark law that presumed to overhaul one-sixth of the U.S. economy isn't out of the legal woods.

According to a 2-1 decision announced Tuesday by a panel of the federal Court of Appeals in the District of Columbia, the law "plainly makes subsidies [for insurance premiums paid by qualifying individuals] available only on exchanges established by states."

The judicial panel ruled that if you buy your health insurance policy on a federal exchange, as required in the 27 states (including South Carolina) that have not set up their optional state health insurance exchanges, or in the nine states that have partially opted out, you do not qualify for a subsidy even if you meet the income guidelines.

The ruling, however, won't go into effect until the appeal of it is resolved.

Numerous experts agree with the White House's prediction that the full D.C. Court of Appeals, where seven of the 11 jurists were appointed by Democratic presidents, will reverse the panel's decision.

If so, though, that outcome would assuredly be appealed to the Supreme Court. And if the justices decide that Americans in 36 states won't be able to get those federal subsidies, Obamacare's already-shaky foundation will suffer a potentially crippling blow.

The panel's majority opinion, drafted by Republican-appointed Judges Thomas Griffith and Arthur Randolph, logically asserted: "To hold otherwise would be to say that enacted legislation, on its own, does not command our respect - an utterly untenable proposition."

Plaintiffs in the case stressed that Congress nowhere indicated, in the law or supporting legislative history, any intention of providing subsidies except through state exchanges.

Judge Harry Edwards, a Democratic appointee, countered that the decision "defies the will of Congress and the permissible interpretations of the agencies to whom Congress has delegated authority."

Still, Congress is supposed to clearly define its will in legislative language. It failed to do so here. Perhaps that was because the Democratic leadership was in such a rush to pass the bill, which got through both chambers of Congress without a single Republican vote - and with 34 House Democrats voting against it.

Also on Tuesday, however, a panel of the 4th Circuit Court of Appeals in Richmond, Va., found that legislation's language sufficiently ambiguous on the subsidies to let the administration provide them in states without exchanges.

But President Obama has severely tested the limits of executive authority by repeatedly issuing constitutionally questionable fiats delaying some of the law's key mandates. Last week, the administration even released the five U.S. territories, at their request, from nearly all major provisions of Obamacare - another shift made without seeking congressional approval. The White House's habit of unilaterally changing the law has added more costly uncertainty to its negative effects on the American economy.

The Supreme Court's 5-4 decision that upheld Obamacare in 2012 also injected a dose of bewilderment. In that ruling, Chief Justice John Roberts defined the proscribed "fine" imposed on those who fail to buy health insurance as a "tax."

Maybe it should come as no surprise that Obamacare remains such a puzzle, even to the federal judiciary. After all, Nancy Pelosi, then speaker of the House, infamously told the Legislative Conference of the National Association of Counties back in 2010 that Congress had to pass the bill "so that you can find out what is in it away from the fog of the controversy."

But now in 2014, controversy endures about what Obamacare is - and what it isn't.

And it's increasingly likely that the Supreme Court will eventually get another crack at providing those answers.