Acquiescence is a legal term used to describe an act where a person knowingly stands by without raising any objection to the infringement of their rights, while someone else unknowingly and without malice aforethought makes a claim on their rights. Consequently, the person whose rights are infringed loses the ability to make a claim against the infringer, or succeed in an injunction suit due to the infringer's conduct. The term is most generally "permission" given by silence or passiveness. Acceptance or agreement by keeping quiet or by not making objections.
The common law doctrine of estoppel by acquiescence is applied when one party gives legal notice to a second party of a fact or claim, and the second party fails to challenge or refute that claim within a reasonable time. The second party is said to have acquiesced to the claim, and is estopped from later challenging it, or making a counterclaim. The doctrine is similar to, and often applied with, estoppel by laches.
This occurred in the second Georgia v. South Carolina[1] case before the U.S. Supreme Court in 1992, when it was ruled that Georgia could no longer make any claim to an island in the Savannah River, despite the 1787 Treaty of Beaufort's assignment to the contrary. The court said that the state had knowingly allowed South Carolina to join the island as a peninsula to its own coast by dumping sand from dredging, and to then levy property taxes on it for decades. Georgia thereby lost the island-turned-peninsula by its own acquiescence, even though the treaty had given it all of the islands in the river (see adverse possession).
The doctrine of acquiescence although typically not found in law, is found a lot in precedent. As seen by this search of US Supreme Court rulings, the doctrine of acquiescence has been mentioned over a thousand times.
Silence is acquiescence (aka. silent acquiescence and acquiescence by silence) is a related doctrine that can mean, and have the legal effect, that when confronted with a wrong or an act that can be considered a tortious act, where one’s silence may mean that one accepts or permits such acts without protest or claim thereby loses rights to a claim of any loss or damage.[2]