We’ve got a discussion going. Excellent! In “The Problematic Halbig Decision: Why “Intent” is Too Narrow an Inquiry”, David Gamage tells us that he and others who were making regulations based on the new statute didn’t even hear mention of the possibility that non-participating states wouldn’t get subsidies for many months. That’s what the House oversight report says about Treasury at the time too. So the Executive branch didn’t see any problem till it was pointed out to them from outsiders.
This evidence cuts both ways, though. Notice that nobody says that Treasury officials read the subsidy clause and said, “Hey, there might be a problem because that language seems to exclude subsidies for federal exchanges.” Why, when so many people now see a problem? My guess is that they were working frantically to implement the bill (remember the federal exchange rollout fiasco and all the deadline changes) and not looking for new problems.
Let’s go back to intent , though. As a bill progresses, clauses are inserted to please this and that group, and often to get just one legislator’s vote. The people who draft the final bill may know very well what they’re doing, and hate the result compared to the draft-before-final, but insert the obnoxious clause knowingly because they need it to pass the bill. They may then employ a useful bureaucratic trick: put the clause in the document to get agreement, but ignore it in implementation and hope the people who pushed for it don’t notice. (I’ve had that used successfully against me myself more than once!)