His reasoning is completely whackadoodle (legal scholars of all political persuasions are saying so) but here’s what his reasoning is: It’s not controversial that the individual mandate is now unconstitutional now that its fine has been reduced to $0. A prior court case (National Federation of Independent Business v. Sebelius in 2011) ruled that the federal government can only enforce the individual mandate via the Commerce Clause. My understanding of what this means is that the only way in which the government has the authority to punish you for not buying something is to impose a tax penalty. During the 2017 Tax Cuts and Jobs Act, the individual mandate was basically overturned but not actually. That is, what they did was they reduced the fine for not buying insurance to $0. It is still technically illegal to not have insurance, but the punishment for doing so is nothing except a fine of $0. In the current case, Texas v. US, the plaintiff is arguing that the individual mandate is now unconstitutional because it is not being enforced via the Commerce Clause as a tax penalty. That much is pretty easy to accept. So the individual mandate should be struck down – which amounts to absolutely nothing, as the only thing that happens is that that fine of $0 goes away. What happens from there is the judge must consider the “severability” of the individual mandate – that is, can the rest of the law exist without it? To me, arguing that it can’t is absolutely nuts. This judge is effectively saying that this fine of $0 is such an important part of the law that the rest cannot exist without it. Another thing that is relevant to severability is the will of Congress. The judge is trying to interpret what Congress would have done with the rest of the law if they had known that the individual mandate portion was unconstitutional. He’s claiming that, in this situation, the 2017 Congress which passed the Tax Cuts and Jobs Act would have overturned the whole ACA rather than choosing to dispose of just the $0 fine. That’s nuts as well – we know they didn’t want to do that because they voted against a full repeal of the ACA multiple times. If there is any justice left in this land, this case will get laughed out of the Fifth Circuit Court of Appeals and this decision will get thrown away. I am still terrified, though.