The laches defense is an equitable rule that lets a court throw out an otherwise valid lawsuit when the plaintiff waited too long to file and that delay actually hurt the defendant. It is not a fixed deadline. A judge decides, case by case, whether the wait was unreasonable and whether the defendant suffered real harm because of it. Two recent Supreme Court decisions have narrowed where the defense works, but it remains a live threat in trademark, real property, employment, and certain patent disputes.
The Two Things a Defendant Must Prove
A defendant invoking laches carries the full burden on both elements. Falling short on either one sinks the defense.
The first element is unreasonable delay. The clock starts when the plaintiff knew, or reasonably should have known, about the potential claim, not when the harm first occurred. There is no bright-line rule for how many months or years count as unreasonable. Judges weigh the complexity of the dispute, whether the plaintiff was actively trying to resolve things out of court, and whether an agency investigation was underway. A plaintiff who simply went quiet with no explanation has a problem. A plaintiff who spent the same period in settlement talks or waiting on a regulator usually does not.
The second element is actual prejudice. Time alone is never enough. The defendant has to show the delay caused real harm to their legal position or finances. A defendant who sailed through the plaintiff’s silence unaffected cannot invoke laches no matter how long the wait.
How Laches Differs From a Statute of Limitations
Statutes of limitations are hard deadlines set by legislatures. Three years for a personal injury case, six for a contract dispute, whatever the legislature chose. Miss the window and the claim is dead, period.
Laches is different. It is a judge-made rule of fairness. A court can apply it even when the statute of limitations has not yet expired, though doing so usually requires especially strong facts. The reverse also holds: filing within the statutory window does not automatically immunize a plaintiff from laches, at least where equitable relief like an injunction is on the table.
In many trademark cases, courts borrow the most analogous state statute of limitations as a yardstick. If the plaintiff’s delay exceeds that period, some courts presume laches applies and shift the burden to the plaintiff to justify the wait. If the delay is shorter, the presumption flips and the defendant has the heavier load.
When Laches Cannot Bar a Claim
Two Supreme Court rulings have taken laches off the table for damages claims brought inside a federal statute of limitations.
In Petrella v. Metro-Goldwyn-Mayer, Inc. (2014), the Court held that laches cannot bar a copyright infringement claim for damages brought within the Copyright Act’s three-year window. Congress had already made a timeliness judgment by setting a statute of limitations, and laches should not override that choice when the plaintiff is seeking legal rather than equitable relief. The Court left open the possibility that laches could still affect equitable remedies even within the statutory period.1Justia. Petrella v. Metro-Goldwyn-Mayer, Inc., 572 US 663 (2014)
Three years later, SCA Hygiene Products Aktiebolag v. First Quality Baby Products, LLC (2017) extended the same logic to patent law. Laches cannot be invoked against a patent infringement damages claim when the alleged infringement falls inside the Patent Act’s six-year period.2Supreme Court of the United States. SCA Hygiene Products Aktiebolag v. First Quality Baby Products, LLC
The practical takeaway is simple. If a federal statute sets a limitations period and the plaintiff files within it, laches will not wipe out a damages award. The defense can still shape whether the court grants equitable relief like an injunction or an accounting of profits. A plaintiff who sat on their rights for years may collect their damages check and still find the court unwilling to order the defendant to stop.
Where the Defense Still Matters
Trademark Disputes
Lanham Act cases are the busiest ground for laches. The statute itself lists it as a defense to an incontestable registration. A trademark owner who watches a competitor use a confusingly similar mark for years without objecting can lose the ability to get an injunction. Whether laches can also eliminate monetary relief in Lanham Act cases after Petrella remains unsettled across the circuits.
One doctrine protects trademark owners from being trapped by their own patience. Under progressive encroachment, a plaintiff who tolerated low-level or distant use of a similar mark can still sue when the defendant materially expands into new markets or product lines. The original restraint was reasonable given the limited scope; the expansion changed the picture enough to restart the clock.
Patent Cases
Before SCA Hygiene, laches was a standard patent defense. Now it is confined to arguments about equitable relief. A patent holder who delays can still recover damages inside the six-year lookback, but a court may weigh the delay when deciding whether to issue an injunction.2Supreme Court of the United States. SCA Hygiene Products Aktiebolag v. First Quality Baby Products, LLC
Real Property and Boundary Disputes
Laches shows up often in quiet title actions, boundary fights, and easement disputes. If a landowner knows a neighbor is encroaching or using a disputed path and does nothing for years while the neighbor invests in improvements, a court may refuse to order removal. These cases produce strong economic prejudice arguments because construction costs are easy to quantify.
Employment Discrimination
Courts have allowed laches defenses against the EEOC in employment discrimination enforcement actions. The relevant delay is the gap between the end of conciliation and the filing of suit, not the time the charge was under investigation. The employer still has to show actual prejudice, such as lost personnel records or departed witnesses.3Justia. EEOC v. Watkins Motor Lines, Inc., 463 F3d 436
What Counts as Prejudice
Courts recognize two main forms.
Evidentiary prejudice is the intuitive kind. Witnesses die or move away, memories fade, documents get destroyed in routine purges, electronic records become unreadable. A defendant who can no longer reconstruct what happened has been genuinely harmed. Judges give this argument more weight when the missing evidence goes to the heart of the defense rather than a side issue. A defendant who lost one witness but still has thorough documentation may not clear this bar.
Economic prejudice is about financial position. A company that invested heavily in a product line, built a brand, or developed real estate while the plaintiff watched and said nothing has committed money in reliance on the apparent acceptance of the situation. Judges look at the scale of the investment, whether the defendant knew about the potential claim when they spent the money, and whether the investment would have happened regardless of the lawsuit.
When Delay Is Excusable
Not every wait counts against the plaintiff. Courts regularly accept the following explanations:
- Active negotiations or mediation. Time spent trying to resolve the dispute without litigation shows good faith, not neglect.
- Pending government investigation. A plaintiff who waits for a regulator to finish before filing has a legitimate reason for the gap.
- Inability to discover the claim. If there was no reasonable way to learn about the conduct, the clock does not start until discovery was possible.
- The defendant’s own concealment. A defendant who hid the conduct is in a poor spot to argue the plaintiff should have acted sooner.
The line that matters is between active pursuit and dormancy. Three years in settlement talks reads very differently from three years of silence.
Laches Against the Government
Laches generally cannot be raised against the federal government. The principle traces to the old common-law maxim that time does not run against the sovereign, and it survives in modern regulations. Under 43 CFR ยง 1810.3, the United States’ authority to enforce a public right or protect a public interest is not lost through the acquiescence, laches, or delays of its officers.4eCFR. 43 CFR 1810.3 – Effect of Laches; Authority to Bind Government
Courts have carved out exceptions in specific contexts. The EEOC has faced successful laches defenses in employment enforcement actions when its delay after completing an investigation caused demonstrable harm to the employer.3Justia. EEOC v. Watkins Motor Lines, Inc., 463 F3d 436
Laches vs. Equitable Estoppel
The two defenses overlap but are not the same. Both turn on the plaintiff’s conduct and the defendant’s reliance, and both protect against unfairness, but they target different kinds of it.
Laches is about unexplained inaction. The plaintiff knew about a claim and sat on it, and the delay itself caused harm. There is no requirement that the plaintiff said anything or communicated at all. Silence plus prejudice is enough.
Equitable estoppel is narrower. It requires the plaintiff to have done or said something misleading, and the defendant must have relied on that conduct to their detriment. The classic scenario involves a patent holder who sends a demand letter, assures the accused infringer they will not pursue the matter, then reverses course years later after the infringer has built a product line around the disputed technology. Estoppel requires some form of communication or active conduct by the plaintiff; laches requires only silence and delay.
Defendants often plead both when the facts allow. If the plaintiff simply vanished, laches is the stronger argument because estoppel’s communication requirement will be hard to satisfy.
How to Raise It
Laches is an affirmative defense under Rule 8(c)(1) of the Federal Rules of Civil Procedure, which means the defendant must raise it in the initial answer to the complaint.5Legal Information Institute. Federal Rules of Civil Procedure Rule 8 – General Rules of Pleading Missing that window is serious. Courts routinely treat affirmative defenses as waived when a defendant fails to plead them in the answer. First mentioning laches at summary judgment or trial risks having the argument rejected entirely. Because the defense depends on case-specific facts rather than a fixed deadline, trial judges have broad discretion in applying it, and appellate courts will disturb that ruling only for an abuse of discretion.