We talk about the Law of Unintended Consequences, and we make it sound like the proponents of whatever less-than-optimal scheme has just blown up, as such schemes will, had no idea that this sort of thing could possibly happen.
I’ve never seen one adduced that wasn’t actually in truth anticipated. It’s just that, at the time folks were you know anticipating, they were being called naysayers or sticks-in-the-mud or that sort of thing by proponents of the move which engendered the consequences. So, rather than accept the excuse and forgiveness implied in the “unanticipated” part, I’d call them “unacknowledged” consequences. Or “glossed over” consequences. Or “blithely whistled-past-the-graveyard” consequences.
Add to this modification the virtual certainty that the proponents have made sure that their proposal will have no negative impact on themselves, and you have … well, pretty much an entire session of Congress.