Sen. Mike Lee, R-Utah, was disappointed when the U.S. Supreme Court upheld Obamacare. One year later — having thought about the case, gotten some distance from the issue, reviewed the ruling opinion — he’s confident of one thing: Chief Justice John Roberts engaged in “a betrayal of his judicial oath,” one that amounts to “a form of tyranny.”

“In this case, I can’t be sure what exactly motivated Chief Justice John Roberts,” Lee said last night during a Charles Koch Institute event on “Freedom, Laws, and the Commerce Clause” at the Kirby Center for Constitutional Studies. “But what we do know is this: in this case, he appears to have undertaken a ‘split the baby strategy.’ It didn’t work. [It's] not just that it didn’t work, but it amounted, I believe, to a betrayal of his judicial oath. He engaged in law-making and this is wrong.”

Lee acknowledged that it’s a bit uncomfortable to criticize Roberts, due to his respect for the chief justice (a friend of the late Rex Lee, the senator’s father) and for the Supreme Court as an institution.

“Here’s how I justify it in my own mind,” he said. “John Roberts did my job. I would not be criticizing him had he not treaded on my grass. He did my job and I’m going to call him out on it.”

To that end, Lee — who has just published a book about Why John Roberts Was Wrong About Health Care — cited Roberts’ reading of the individual mandate as a tax as one of two examples of this legislating from the bench.

“Congress tried to push [the individual mandate] through initially as a tax, but couldn’t because it couldn’t get the votes . . . the Supreme Court did for Congress what Congress was unable to obtain the votes to do,” Lee said, before reminding his audience that the Constitution demands that tax bills originate in the House of Representatives because those legislators face voters every two years. “Here, you have a tax increase that was not only initiated in the House of Representatives, it was not initiated anywhere in Congress. It was never enacted in Congress. It was enacted by five lawyers wearing black robes who will never, ever stand for election.”

Congress clearly did not exercise it’s taxing power, Lee said. “Under about a century’s worth of jurisprudence — of legal rules, of court precedent from the Supreme Court — there is no way to read the language enacted by Congress in the individual mandate as a tax,” he said. “This one is a penalty. There is nothing about it that can be defended as a tax.”

Lee also suggested that the Supreme Court’s decision on the Medicaid expansion “is even worse,” even though many conservatives hailed that as a victory of sorts because the Supreme Court ruled that the federal government could not order states to expand their Medicaid programs, as Obamacare attempted to do.

“That — as seven members of the Supreme Court, including Chief Justice Roberts — concluded, was plainly unconstitutional,” Lee said of the Medicaid provision in the health care law.  “But then he said, ‘don’t worry, because we’re just going to read this as if it contained an opt-out provision for the states so that any state that doesn’t want to expand its Medicaid program doesn’t have to. And as long as we read it that way, then it’s constitutional.’”

Of course, the law as written does not contain an opt-out provision. Lee thinks Roberts decided to read one into the law because the Medicaid expansion provision, if struck down, was “not severable” from the rest of the law.

“The unconstitutionality even of just the Medicaid expansion provisions would have been enough to sink the entire ship,” Lee said. “[Roberts] saw that that was going to happen and so he saved it by rewriting it. So the chief justice chose to rewrite the law — not just once, but twice. And as a result we now have on the books — in its operation, in its practical application — an act of Congress that was never passed. It’s not just that nobody read it. It’s not just that Congress didn’t read Obamacare before they passed it. They didn’t pass the actual law that’s now in place because it’s been rewritten by five lawyers wearing black robes just across the street from us here. That’s wrong. That’s a form of tyranny under our constitutional system. That’s not how this is supposed to operate.”

The ruling has shaken, though not destroyed, Lee’s confidence in Roberts. “I want to believe this is an aberration,” he told the Washington Examiner after the event. “He had established a reputation as a very careful jurist, during his first seven years or so on the Court, and prior to that on the D.C. Circuit. And so, I hope that’s the real John Roberts . . . only time will tell.”