If you don’t have time today to read Robert Pear’s definitive New York Times piece on the origins of the dispute that has again landed the Affordable Care Act on the docket of the U.S. Supreme Court, book-mark it and read it before SCOTUS acts. After speaking with a bipartisan array of Members and staff involved in drafting and adopting ACA, Pear makes it abundantly clear that the Court has no grounds for ruling for the plaiintiffs in King v. Burwell unless it chooses to embrace a radically restrictive doctrine of legislative interpretation whereby Congressional intent and the logic of the law in question are completely irrelevant.

They are only four words in a 900-page law: “established by the state.”

But it is in the ambiguity of those four words in the Affordable Care Act that opponents found a path to challenge the law, all the way to the Supreme Court.

How those words became the most contentious part of President Obama’s signature domestic accomplishment has been a mystery. Who wrote them, and why? Were they really intended, as the plaintiffs in King v. Burwell claim, to make the tax subsidies in the law available only in states that established their own health insurance marketplaces, and not in the three dozen states with federal exchanges?

The answer, from interviews with more than two dozen Democrats and Republicans involved in writing the law, is that the words were a product of shifting politics and a sloppy merging of different versions. Some described the words as “inadvertent,” “inartful” or “a drafting error.” But none supported the contention of the plaintiffs.

Pear’s major coup was getting former Republican Senator Olympia Snowe, one of a handful of Republicans intimately involved in the crafting of the legislation, on record denying their was ever any intention to make subsidies contingent on state establishment of their own exchanges.

“I don’t ever recall any distinction between federal and state exchanges in terms of the availability of subsidies,” said Olympia J. Snowe, a former Republican senator from Maine who helped write the Finance Committee version of the bill.

“It was never part of our conversations at any point,” said Ms. Snowe, who voted against the final version of the Senate bill. “Why would we have wanted to deny people subsidies? It was not their fault if their state did not set up an exchange.” The four words, she said, were perhaps “inadvertent language,” adding, “I don’t know how else to explain it.”

Pear concludes that the “inadvertent language” was the product of a moment when Finance Committee and HELP Committee provisions were merged. Then, of course, the language was preserved when the House accepted the Senate version of the law to avoid a Republican filibuster after Scott Brown’s special election victory in Massachusetts reduced the number of Senate Democrats to 59. Again, Pear brings in a Republican authority to rebut any revisionist history of what happened:

The idea of denying subsidies to people who bought insurance through the federal exchange “was never discussed,” said Charles M. Clapton, a lawyer who worked on both committees for Senator Michael B. Enzi, Republican of Wyoming. Mr. Clapton said he had difficulty accepting the argument advanced by the plaintiffs because it was “so contrary to the intent” of those who had written the legislation.

It will require a powerful determination on the Court to disrupt the operation of Obamacare, and a willingness to set a dangerous new precedent, for the plaintiffs to win.

Ed Kilgore

Ed Kilgore is a political columnist for New York and managing editor at the Democratic Strategist website. He was a contributing writer at the Washington Monthly from January 2012 until November 2015, and was the principal contributor to the Political Animal blog.