established fact; fait accompli
Refers to a situation that has already happened and cannot be undone, often used in legal, political, or interpersonal contexts where someone creates a fact to force acceptance.
He created a fait accompli and then reported it to his boss.
We have no choice but to accept it as an established fact.
The company created a fait accompli before explaining it to employees.
That decision has already become an established fact.
They tried to turn the occupation into a fait accompli.
The government advanced its plan by accumulating one fait accompli after another.