Необоснованная задержка в предъявлении иска (Neobosnovannaya zaderzhka v pred'yavlenii iska)

Unreasonable delay by a plaintiff in bringing their claim

In common law legal systems, laches ('/l//æ//tʃ//ɪ//z/ LAT chiz '/l//eɪ//tʃ//ɪ//z/; Law French: remissness, dilatoriness, from Old French laschesse) is a lack of diligence and activity in making a legal claim, or moving forward with legal enforcement of a right, particularly in regard to equity. This means that it is an unreasonable delay that can be viewed as prejudicing the opposing party. When asserted in litigation, it is an equity defense, that is, a defense to a claim for an equitable remedy. It is often understood in comparison to a statute of limitations, a statutory defense, which traditionally is a defense to a claim "at law". The person invoking laches is asserting that an opposing party has "slept on its rights", and that, as a result of this delay, circumstances have changed (witnesses or evidence may have been lost or no longer available, etc. ), such that it is no longer a just resolution to grant the plaintiff's claim. Laches is associated with the maxim of equity: "Equity aids the vigilant" not those who sleep on their rights. Put another way, failure to assert one's rights in a timely manner can result in a claim being barred by laches.

Laches is a legal term derived from the Old French laschesse, meaning "remissness" or "dilatoriness", and is viewed as the opposite of "vigilance". The United States Supreme Court case Costello v. United States 365 US 265, 282 (1961) is often cited for a definition of laches. Costello defined Laches as "Lack of diligence by the party against whom the defense is asserted combined with prejudice to the party asserting the defense". Invoking laches is a reference to a lack of diligence and activity in making a legal claim, or moving forward with legal enforcement of a right, in particular with regard to equity, and so is an "unreasonable delay pursuing a right or claim, in a way that prejudices the [opposing] party". The essential element of laches is an unreasonable delay by the plaintiff in bringing the claim; because laches is an equitable defense, it is ordinarily applied only to claims for equitable relief (such as injunctions), and not to claims for legal relief (such as damages). Put another way, failure to assert one's rights in a timely manner can result in a claim being barred by laches. Sometimes courts will also require that the party invoking the doctrine has changed its position as a result of the delay, but that requirement is more typical of the related (but more stringent) defense and equally cause of action of estoppel.

The period of delay begins when the plaintiff knew, or reasonably ought to have known, that the cause of action existed; the period of delay ends only when the legal action is formally filed. Informing or warning the defendant of the cause of action (for example by sending a cease and desist letter or merely threatening a lawsuit) does not, by itself, end the period of delay. The laches defense does not apply if the claimant was a minor during the time that the claim was not brought, so a party can bring a claim against an historical injustice when they reach their majority.

The defense of laches resembles a statute of limitations since both are concerned with ensuring that plaintiffs bring their claims in a timely fashion. However, a statute of limitations is concerned only with the time that has passed. Laches is concerned with the reasonableness of the delay in a particular situation and so is more case specific and more focused on the equitable conduct of the plaintiff. Those considerations are not unique to the laches defense because they are characteristic of equitable reasoning and equitable remedies,

In the Virginia Republican primary for the 2012 US presidential election, several candidates did not appear on the ballot because they failed to obtain sufficient petition signatures. Four of the unsuccessful candidates—Rick Perry, Jon Huntsman, Newt Gingrich, and Rick Santorum—sued, claiming that restrictions on the persons allowed to gather signatures were unconstitutional. Their claim was dismissed by the district court on the grounds of laches, because, in the words of the appellate court: The appeals court upheld the dismissal on grounds of laches, but it added that the challenge would likely have succeeded if it had been brought in a timely fashion. The defense of laches is often used as an affirmative defense in patent infringement lawsuits in the USA. In 2021, the Court of Appeals for the Federal Circuit allowed the USPTO to use laches as a reason for denying patents to an applicant, who filed hundreds of applications, that were "atypically long and complex", and who filed amendments, which increased the total number of claims to roughly 115,000. This applicant alone forced the USPTO to create an art unit of twelve experienced examiners solely to examine its patents.