fait accompli

noun2

1. •
   Something which has already happened, before those affected had the chance to raise objections or queries; especially, such a thing that cannot be undone.

   • Thanks to a bureaucratic fait accompli, the demolition was already approved and has already started.
2. •
   An action or establishment that cannot be undone.

   • The introduction of white clover to the Americas is a fait accompli.