Do you have the patience for another postscript on the weird but momentous U.S. Supreme Court decision upholding the constitutionality of the Affordable Care Act, or “Obamacare”?

The big question, left unanswered by all the court’s opinions in the case and the millions of words of commentary, is the extent to which politics, not the law, determined how five of the nine justices came down on the healthcare law.

It turns out that the people of Arkansas are in a better position to answer that question than anyone in America. More about that in a minute.

First, as everyone knows, Chief Justice John Roberts shocked the Republican Party and his Republican colleagues on the court by straying from the fold on one of the three big issues in the case, which resulted in the court upholding the law by a vote of 5 to 4. As expected, Roberts had joined the four other conservatives in holding that the Constitution’s commerce clause did not allow the federal government to regulate health insurance by requiring the uninsured to buy insurance if they could afford it. But then, to the others’ dismay, Roberts said the law was constitutional on a separate ground — that the mandate for people to pay a small tax if they refused to insure themselves was a permissible thing for Congress to do — so the mandate was constitutional after all.

Since then, the conjecture has been that George W. Bush’s chief justice switched on the weird little tax question because he was concerned about the image of his court — that it decided things based on which political party favored them and not upon an impartial reading of the law. Surveys show that most people already believed it — the evidence, after all, was overwhelming — but that most people were OK with a political decision if they liked the result. And more people were hoping Obamacare would be thrown out than hoped it would be upheld.

Now, to the question of whether this was, indeed, a political decision: All you really need to do is ask whether the five Republican justices would have held that the commerce clause forbade the insurance mandate if Congress had passed essentially the same law when Presidents Nixon and Ford proposed it in the 1970s or when, in the 1990s, the Republican leadership of Congress proposed it. To ask the question is to answer it.

But we in Arkansas have a definitive answer to the question without resorting to speculation. In a quite similar case, with far-reaching consequences for people and business in Arkansas, the U.S. Supreme Court upheld even more drastic federal power over what people were compelled to buy under the commerce clause. The justices who led the way: Antonin Scalia and Anthony Kennedy, the only current justices who were on the court back in 1987 when the case was decided. Scalia wrote the stinging opinion for the court last month attacking Obamacare and claiming that the commerce clause prohibited such use of federal power. Regulating “inactivity” by consumers was going too far for the federal government, Scalia, Kennedy, Roberts, Samuel Alito and Clarence Thomas said.

Unheard of, they said.

I’m sorry. We’re going to have to talk again about Grand Gulf, the big electricity dispute that baffled the people of Arkansas for 30 years and cost them at last count $4.5 billion — $6,500 on average for each homeowner and business in Arkansas.

The Supreme Court — Scalia, Kennedy, Chief Justice William Rehnquist (Justice Roberts’ old boss and mentor) and others — ruled in 1987 that the Federal Energy Regulation Commission (FERC) was perfectly within its power under the commerce clause to make utilities in Arkansas and Mississippi and their customers pay for power they did not need and could not use so that utility investors could reap a profit on their investment. FERC — this was Ronald Reagan’s agency and not Obama’s — sided with Middle South Utilities, which wanted to make people in Arkansas, Mississippi and Louisiana pay for a giant nuclear power plant in Mississippi that the utilities built as a result of a monumental misjudgment on the need for it and its cost.

The liberals on that court, all gone now, thought the commerce clause restricted FERC’s power in such matters and that states could decide on their own if the utilities were imprudent in building the plant and if people in Arkansas and Mississippi could be forced to pay for electricity they didn’t need. It seemed manifestly unfair since Arkansas had built two nuclear units and giant coal-burning units at White Bluff and Newark, and Arkansas customers already were paying high rates for them.

Arkansas, you may remember, was forced to pay for more than 32 percent of the Grand Gulf capacity and to subsidize Louisiana ratepayers to boot. Arkansas hopes to extricate itself from the FERC and Supreme Court orders next year by leaving the old Middle South (now Entergy) power pool and joining another.

It is still nightmarish to read, but you can follow Scalia’s and Kennedy’s views on the commerce clause back then and compare them to their ideas on the same issue last month. Scalia wrote in ’87 that Reagan’s agency “plainly” had the power under the commerce clause to find jurisdiction for itself in congressional statutes on energy regulation.

The old liberals — Thurgood Marshall, William Brennan and Harry Blackmun — scolded Scalia. The energy statute itself restrained FERC’s power without resorting to the commerce clause, they said.

Let’s summarize. The conservative justices who thought it was fine under the commerce clause for the Reagan administration to require Arkansans to pay $4.5 billion to guarantee a profit for Middle South and subsidize the electric rates of people to their south claimed in 2012 that the same clause barred Congress and the Obama administration from requiring uninsured people to buy insurance or pay a small tax to help the government pay for their unreimbursed medical care.

What changed? No need to guess.