Congress enacts a law imposing safety obligations on frontier AI developers
The index says: very unlikely (12%). Graded on that date, right or wrong, in public.
Why the index thinks so
The lame-duck NDAA is the only realistic vehicle; Metaculus gives 24% for a kill-switch bill passing both chambers and 5.5% for a federal AI-hacking liability law, and House leadership has said Congress shouldn't lead on AI safety rules.
What would move it
NDAA conference text; Senate Commerce markups; a major incident shifting votes.