The Preliminary Injunction Standard: Winter, the Sliding-Scale Split, and Rule 65

A preliminary injunction requires four showings under Winter v. NRDC: that you are likely to succeed on the merits, likely to suffer irreparable harm without relief, that the balance of equities tips in your favor, and that an injunction is in the public interest. Circuits split on whether a strong showing on one factor offsets a weak one.

That last sentence is what most guides skip, and it decides whether you file.

This article is for general information and is not legal advice. For guidance on a specific case, consult a licensed attorney in your jurisdiction.

The four Winter factors

Winter v. Natural Resources Defense Council, Inc., 555 U.S. 7 (2008), at 20:

A plaintiff seeking a preliminary injunction must establish that he is likely to succeed on the merits, that he is likely to suffer irreparable harm in the absence of preliminary relief, that the balance of equities tips in his favor, and that an injunction is in the public interest.

The holding that changed practice is narrower. The Ninth Circuit had allowed relief on a mere possibility of irreparable harm where the merits were strong. The Ninth Circuit's "'possibility' standard is too lenient," the Court held; "[o]ur frequently reiterated standard requires plaintiffs seeking preliminary relief to demonstrate that irreparable injury is likely in the absence of an injunction." An injunction is "an extraordinary remedy never awarded as of right," available only "upon a clear showing that the plaintiff is entitled to such relief." Id. at 22, 24. The same four factors govern National Labor Relations Board § 10(j) petitions. Starbucks Corp. v. McKinney, 602 U.S. 339 (2024).

Against the government, you brief three factors, not four. Nken v. Holder, 556 U.S. 418, 435 (2009): "[t]he third and fourth factors, harm to the opposing party and the public interest, merge when the Government is the opposing party." Courts apply that merger routinely to government defendants.

The split that decides whether you file

Winter said what the factors are. It did not say how they combine. Two camps exist, and yours changes the motion.

Camp one: the factors slide. A stronger showing on one element offsets a weaker showing on another. Alliance for the Wild Rockies v. Cottrell, 632 F.3d 1127, 1135 (9th Cir. 2011) held that the sliding scale survives Winter if all four elements are addressed:

"[S]erious questions going to the merits" and a balance of hardships that tips sharply towards the plaintiff can support issuance of a preliminary injunction, so long as the plaintiff also shows ... a likelihood of irreparable injury and that the injunction is in the public interest.

The Second Circuit agreed in Citigroup Global Markets, Inc. v. VCG Special Opportunities Master Fund Ltd., 598 F.3d 30, 35 (2d Cir. 2010), reasoning that the burden is no lighter because the hardships must tip decidedly. So did the Seventh, framing it as net harm. Hoosier Energy Rural Electric Cooperative, Inc. v. John Hancock Life Insurance Co., 582 F.3d 721, 725 (7th Cir. 2009).

Camp two: each factor is an independent requirement. The Fourth Circuit abandoned its own sliding scale in Real Truth About Obama, Inc. v. FEC, 575 F.3d 342, 346-47 (4th Cir. 2009), reinstated in relevant part, 607 F.3d 355 (4th Cir. 2010) (per curiam). Winter "articulates four requirements, each of which must be satisfied as articulated," and its demand for a clear showing of likely success "is far stricter than" a rule asking only for "a grave or serious question for litigation."

Do not take that on faith for your own court. Positions have moved since Winter, some circuits have spoken only in dicta, and judges read precedent differently. Pull the latest published opinion from your circuit: finding controlling authority and confirming it is still good law is the first hour's work, not the last.

Irreparable harm is where the motion dies

Most denials turn on harm money can fix, or a movant who waited.

Money defeats it. Sampson v. Murray, 415 U.S. 61, 90 (1974): "The possibility that adequate compensatory or other corrective relief will be available at a later date, in the ordinary course of litigation, weighs heavily against a claim of irreparable harm." A declaration quantifying the loss in dollars writes the opposition's best paragraph.

Delay defeats it. In Benisek v. Lamone, 585 U.S. 155 (2018) (per curiam), the Court affirmed a denial partly because "a party requesting a preliminary injunction must generally show reasonable diligence." If there is a gap between the triggering event and your filing, explain it in the opening declaration.

What qualifies. Loss of First Amendment freedoms, "for even minimal periods of time," under Elrod v. Burns, 427 U.S. 347, 373 (1976). Intangible business injuries too: "[i]ntangible injuries, such as damage to ongoing recruitment efforts and goodwill, qualify as irreparable harm." Rent-A-Center, Inc. v. Canyon Television & Appliance Rental, Inc., 944 F.2d 597, 603 (9th Cir. 1991). Also recurring: disclosure of trade secrets or privileged material, destruction of unique property, collapse of a business as a going concern. Each needs evidence, not adjectives.

TRO versus preliminary injunction under Rule 65

Rule 65 governs both, but they are different instruments.

The ex parte showings. Rule 65(b)(1)(A) requires "specific facts in an affidavit or a verified complaint" clearly showing "immediate and irreparable injury, loss, or damage ... before the adverse party can be heard in opposition." Rule 65(b)(1)(B) requires that "the movant's attorney certifies in writing any efforts made to give notice and the reasons why it should not be required." That certification is a separate signed document, not a sentence in the brief; omitting it is a common reason applications come back unsigned.

The 14 days. A TRO issued without notice "expires at the time after entry — not to exceed 14 days — that the court sets," unless the court extends it "for a like period" for good cause or the adverse party consents to longer. Rule 65(b)(2). The order must state the date and hour it issued, describe the injury, and say why it is irreparable and why it issued without notice.

Appealability. 28 U.S.C. § 1292(a)(1) makes interlocutory orders "granting, continuing, modifying, refusing or dissolving injunctions" immediately appealable. A TRO generally is not; the exception, from Carson v. American Brands, Inc., 450 U.S. 79 (1981), reaches an order with the practical effect of an injunction that "might have a serious, perhaps irreparable, consequence."

The bond, and who the order actually binds

Rule 65(c) surprises solos at the worst moment: a court may issue an injunction or TRO "only if the movant gives security in an amount that the court considers proper to pay the costs and damages sustained by any party found to have been wrongfully enjoined or restrained." The United States and its agencies are exempt. Courts treat the amount as discretionary and many set a nominal figure where harm to the restrained party is speculative, but that discretion is not self-executing. Propose a number, with a declaration on why the restrained party faces no quantifiable loss. Say nothing and you invite a figure your client cannot post — a denial by another route.

Rule 65(d)(1) requires the order to state the reasons it issued, state its terms specifically, and "describe in reasonable detail — and not by referring to the complaint or other document — the act or acts restrained or required." Rule 65(d)(2) limits reach: it binds only those "who receive actual notice of it by personal service or otherwise" — the parties, their officers, agents, employees and attorneys, and persons "in active concert or participation" with them. Draft the order yourself, in operative verbs, and serve everyone whose conduct you need to reach.

The papers, and a realistic 48-hour timeline

An emergency application is four documents plus exhibits: the motion, a memorandum, declarations carrying every fact you rely on, and a proposed order, plus the Rule 65(b)(1)(B) certification if you go ex parte. Read the local rules and the judge's standing order first.

1. Hours 0-4. Confirm jurisdiction and venue, identify the claim supporting equitable relief, and pull your circuit's statement of the standard. Decide TRO or preliminary injunction now; it changes the papers.
2. Hours 4-12. Draft the client declaration first; the irreparable-harm section is only as strong as the sworn detail behind it.
3. Hours 12-28. Write the memorandum. Lead with irreparable harm in a sliding-scale circuit when the merits are close; lead with the merits where each factor stands alone. Draft the order in parallel.
4. Hours 28-40. Verify every citation and quotation, then confirm each case is still good law. Rule 11 exposure does not soften because you were in a hurry.
5. Hours 40-48. Give notice, file, and call chambers if the local rules direct it.

Step four is what gets compressed and what should not be. Tools built for litigation work help only if they retrieve authority rather than compose it: CaseRead links each citation to the source it retrieved and flags what it cannot verify. Seeking the injunction or opposing it, the analysis lands where summary judgment does: what does controlling authority here require, and can you prove it on this record.

Frequently asked questions

What is the standard for a preliminary injunction?

Under Winter v. Natural Resources Defense Council, 555 U.S. 7, 20 (2008), the movant must establish likely success on the merits, likely irreparable harm without relief, a balance of equities tipping in its favor, and that an injunction serves the public interest. Starbucks Corp. v. McKinney, 602 U.S. 339 (2024), reaffirmed it.

How long does a temporary restraining order last in federal court?

A TRO issued without notice expires at the time the court sets, not to exceed 14 days after entry. Rule 65(b)(2) allows one extension for a like period on good cause, with the reasons entered in the record, or a longer extension if the restrained party consents.

Do you have to post a bond to get a preliminary injunction?

Rule 65(c) permits an injunction or TRO only if the movant gives security in an amount the court considers proper to cover costs and damages to a party wrongfully enjoined. The United States and its agencies are exempt. Courts treat the amount as discretionary, so propose a specific figure in the motion.

Can you appeal the denial of a preliminary injunction?

Yes. Under 28 U.S.C. § 1292(a)(1), interlocutory orders granting, continuing, modifying, refusing, or dissolving injunctions are immediately appealable. A TRO generally is not. Carson v. American Brands, 450 U.S. 79 (1981), allows an appeal from an order with the practical effect of an injunction that threatens serious, perhaps irreparable, consequences.

What counts as irreparable harm?

Harm money cannot fix. Sampson v. Murray, 415 U.S. 61, 90 (1974), says the availability of later compensatory relief weighs heavily against it. Courts have found it in the loss of First Amendment freedoms, Elrod v. Burns, 427 U.S. 347, 373 (1976), and in intangible business harm such as lost goodwill, Rent-A-Center v. Canyon Television, 944 F.2d 597, 603 (9th Cir. 1991).

Before you file it

If any part of your motion, declaration, or proposed order passed through a general-purpose AI tool, run it through the Hallucination Shield first. It is free, needs no signup, and each citation it finds — up to 25 per run — is checked for existence and for whether the source supports the proposition. Faster than cite-checking the brief by hand at midnight.