I wish I saw this first. I'm very prone to off-by-one errors.
I opened the comments thinking that I solved it, then some comments with broken spoiler tags essentially spoiled the actual answer for me, despite my best efforts to ignore them.
With these types of puzzles, I normally start looking for solutions that don't just involve the obvious operations. Had I seen your comment first, I would've continued playing with the first thing I noticed (and later abandoned for the wrong solution) and I think I would've got there by myself eventually.
Either others need to be more mindful of their spoiler tags, or I need to stop using Sync for Lemmy. It's probably the latter; I've seen such weird formatting that only makes sense if I assume Sync's Markdown renderer is broken.
Seems like the "state-ratifying conventions" route is the only thing that has a chance of working, and that's ignoring that the Constitution doesn't regulate them.
Although, seeing as an amendment need 2/3rds of each chamber of Congress to pass, regardless of sending it to the legislatures or conventions (not for the convention to propose amendments), could Congress use that veto-proof majority to pass a law regulating conventions?
Whatever the idea, pretty sure this ends up in the Supreme Court regardless?
... is it weird that I've been thinking about this for the last decade? I'm not even American.