Preliminary injunction examples typically fall into three recurring patterns: a company trying to stop a departing employee from exposing trade secrets, a property owner trying to halt irreversible destruction during a boundary or ownership dispute, and an individual or organization trying to block a government policy that restricts constitutional rights. In each situation, a court issues an early order freezing the situation in place because waiting for trial would cause harm that money cannot later repair.
The Four Factors Behind Every Example
Every preliminary injunction, regardless of the subject matter, is decided under the four-factor test the Supreme Court set out in Winter v. Natural Resources Defense Council, Inc. (2008). The requesting party must show a likelihood of success on the merits, irreparable harm without the order, a balance of hardships tipping in their favor, and that the injunction serves the public interest.1Legal Information Institute. Preliminary Injunction
Likelihood of success does not mean a guarantee. The judge looks at the claims and the evidence filed so far and asks whether the case appears strong enough to justify intervening before trial. Irreparable harm has to be concrete and probable, not hypothetical, which is why unique property, confidential information, and constitutional rights come up so often in granted injunctions.2Legal Information Institute. Irreparable Harm The balance of hardships compares how much each side suffers under the two possible outcomes, and the public interest factor looks at everyone who is not in the courtroom.
The examples that follow illustrate how those four factors play out in practice.
Example: Trade Secrets After an Employee Leaves
One of the most common preliminary injunction scenarios involves a business trying to prevent a former employee from carrying proprietary information to a competitor. Under the Defend Trade Secrets Act, information qualifies as a trade secret if the owner took reasonable steps to keep it secret and the information has economic value because it is not publicly known.3Office of the Law Revision Counsel. 18 USC 1839 – Definitions
Picture a senior engineer at a chemical company who leaves to join a direct competitor. The engineer had access to proprietary formulas, customer pricing models, and long-term product development plans. The former employer files suit and immediately asks for a preliminary injunction limiting the engineer’s work at the new company. The court evaluates likelihood of success by examining whether the information actually meets the trade secret definition and whether the engineer’s new role creates a substantial risk of disclosure. Irreparable harm is usually easy to show, because once a competitor learns a trade secret, the damage is permanent.
There is an important limit in DTSA cases. The statute specifically provides that an injunction cannot prevent a person from taking a new job. Any restriction a court imposes must rest on evidence of threatened misappropriation, not on the simple fact that the person knows sensitive information.4Office of the Law Revision Counsel. 18 USC 1836 – Private Civil Actions So the order might bar the engineer from working on specific product lines or touching particular data, but it cannot flatly prohibit employment at the competitor.
Example: Stopping Irreversible Property Damage
Property disputes produce some of the clearest preliminary injunction cases because the irreparable harm element almost proves itself. A neighbor starts tearing down a shared historic stone wall in the middle of a boundary fight. A developer begins clearing old-growth trees on land where ownership is contested. A court does not need much convincing that money cannot put any of this back together.
The party seeking the injunction points to surveys, deeds, or historical records to show a likelihood of success on the underlying ownership claim. The balance of hardships usually favors preservation, because the requesting party faces permanent destruction of something irreplaceable while the opposing party faces only a temporary delay. If the land involves environmental features like wetlands or a historically significant structure, the public interest factor also pulls in favor of granting the order.
The injunction keeps the physical situation frozen until the ownership question is resolved at trial. Without it, the winning party at trial might inherit a property stripped of the very features that made it worth fighting over.
Example: Blocking Government Action That Restricts Constitutional Rights
When a government body enacts a policy that immediately restricts fundamental rights, the people affected often seek a preliminary injunction to halt enforcement while the policy’s legality is litigated. The Supreme Court held in Elrod v. Burns that losing First Amendment freedoms, even for a brief period, “unquestionably constitutes irreparable injury.”5Justia Law. Elrod v. Burns, 427 US 347 (1976) That line has become a near-automatic finding of irreparable harm in free speech cases, and courts have extended similar reasoning to other constitutional protections.2Legal Information Institute. Irreparable Harm
The balance of hardships in these cases usually favors the individual. A person whose speech is suppressed suffers a concrete, ongoing loss of a fundamental right. The government’s interest in enforcing the policy, while legitimate, can generally wait for the court to rule on its constitutionality. And the public interest heavily favors protecting constitutional rights during litigation rather than letting a potentially unconstitutional restriction operate unchallenged.
What the 2025 CASA Ruling Changed
For years, examples in this category included nationwide orders. Federal district courts routinely issued preliminary injunctions that blocked a challenged government policy for everyone in the country, not just the named plaintiffs. That changed in 2025. In Trump v. CASA, Inc., the Supreme Court ruled that these “universal injunctions” likely exceed the equitable authority Congress granted to federal courts. The Court held that injunctive relief must be tailored to provide “complete relief” to the specific plaintiffs who have standing to sue, and that complete relief is not the same thing as universal relief.6Supreme Court of the United States. Trump v. CASA, Inc.
So the example still works: a single plaintiff can still obtain a preliminary injunction protecting themselves from an allegedly unconstitutional federal policy. Blocking the policy for everyone, however, now likely requires a certified class action under Rule 23. The Court specifically noted that universal injunctions may impermissibly bypass the procedural protections class actions are designed to provide.6Supreme Court of the United States. Trump v. CASA, Inc.
Preliminary Injunction vs. Temporary Restraining Order
These two remedies get confused constantly, and the difference matters for understanding when each example applies. A temporary restraining order is the emergency version. When harm is so imminent that waiting even a few days for a hearing would be too late, a court can issue a TRO without notifying the other side at all. The applicant must file an affidavit describing the specific threat and explain why notice was impractical.7Legal Information Institute. Federal Rules of Civil Procedure Rule 65 – Injunctions and Restraining Orders
The tradeoff for that speed is a strict time limit. A TRO issued without notice expires within 14 days unless the court extends it for another 14-day period or the restrained party consents to a longer extension. Once it expires, the requesting party either obtains a preliminary injunction through a full noticed hearing or loses the protection.7Legal Information Institute. Federal Rules of Civil Procedure Rule 65 – Injunctions and Restraining Orders
A TRO holds things in place for a few days while the court schedules the preliminary injunction hearing. The preliminary injunction is the sturdier order that lasts through trial. Many of the examples above start with a TRO filed on day one and convert into a preliminary injunction after both sides have appeared.
What Happens If Someone Violates the Order
A preliminary injunction is a direct order from a federal judge, and ignoring it is treated as contempt of court. A party that violates the order can face compensatory fines payable to the other side for any losses caused by the violation, coercive daily fines designed to force compliance, and in extreme cases, jail time until the party agrees to obey. Courts take violations seriously because the entire system of equitable relief depends on parties respecting judicial orders. Treating a preliminary injunction as optional is one of the fastest ways to lose credibility with the judge handling the case.