Acquiescence is the term used to describe an act of a person in knowingly standing by without raising any objection to infringement of his rights, when someone else is unknowingly and honestly putting in his resources under the impression that the said rights actually belong to him. Consequently, the person whose rights are infringed cannot anymore make a claim against the infringer or succeed in an injunction suit due to his 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 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).
Silence is acquiescence 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.
In the United States, certain federal agencies are notorious for practicing nonacquiescence (essentially, ignoring court decisions that go against them). Although executive nonacquiescence has been heavily criticized by the courts, the U.S. Congress has not yet been able to pass a bill formally punishing such behavior.
In one of the most serious instances of nonacquiesence in the U.S., U.S. President Andrew Jackson ignored the U.S. Supreme Court ruling that Georgia had stolen Cherokee lands for the Cherokee Land Lottery in the early 1830s, when the first gold rush occurred. They were then forced off of their own land on the Trail of Tears, shammed in the Treaty of New Echota. The president was never officially held responsible for his blatant contempt of the court, about which he reportedly said: "they have made their decision, now let them enforce it".