Good Law Status: Citators, Flags, and Sanctions Risk

To verify that a case is still good law, run its citation through a citator such as Shepard’s on LexisNexis or KeyCite on Westlaw, read any negative treatment the citator flags to see whether the specific legal point you plan to cite was actually invalidated, and confirm no later statute has overridden the court’s interpretation. That is the whole job in one sentence. The rest is knowing what the signals mean, where they mislead, and what to do when a flag appears.

Before you search anything, pull the citation together. A standard citation has three parts: a volume number, a reporter abbreviation, and a starting page number. In 410 U.S. 113, “410” is the volume, “U.S.” is the United States Reports, and “113” is the first page of the opinion. You also want the deciding court and the year, because the court tells you where the case sits in the hierarchy and the year gives you a starting point for tracking what came after. A transposed digit sends you to the wrong case entirely, so confirm the citation before you rely on any result.

The Three Ways a Case Loses Its Authority

Stare decisis pressures courts to stand by earlier decisions, and as the Federal Judicial Center puts it, judges are “bound to follow that decision so long as it stands unreversed.”¹ Three mechanisms can knock a precedent out.

Overruled

A case is overruled when a higher court, or the same court in a later proceeding, explicitly rejects the legal reasoning behind the earlier decision. Brown v. Board of Education overruling the “separate but equal” doctrine from Plessy v. Ferguson is the textbook example. Once a case is overruled, its central legal principle is no longer controlling law.

Vacated

A vacated decision has been set aside, usually by a higher court finding a procedural defect or a jurisdictional problem in the lower court. The judgment is treated as though it never existed. Vacating differs from overruling because it targets the specific judgment rather than the underlying legal rule.

Superseded by Statute

Legislatures can override judicial interpretations by passing new laws. When Congress or a state legislature disagrees with how a court read a statute, it can amend the statutory language. If the new language conflicts with the court’s prior interpretation, the statute controls, whether or not it mentions the court decision. This is why statutory cases need a legislative check in addition to a case-law check.

Citator Tools

A citator is a database that tracks every later case mentioning a given opinion and categorizes the relationship. It is the only reliable way to run this verification systematically across millions of published decisions.

Commercial Citators

The two dominant professional tools are Shepard’s Citations on LexisNexis and KeyCite on Westlaw. Both assign visual signals for a case’s current status and compile lists of every citing opinion with analysis of how the later court treated the earlier one. LexisNexis subscription plans for law firms currently range from roughly $114 to $432 per month depending on the tier.² Westlaw pricing is comparable but not publicly listed. Many county law libraries provide free on-site access on public terminals.

Attorneys admitted to a state bar may also have free access to Fastcase as a member benefit through every state bar association. Its citator analysis is not as deep as Shepard’s or KeyCite, but it is usable at no cost beyond bar dues.

Free Options

Google Scholar’s “How Cited” tab on any case opinion page lists later cases that reference the decision and shows excerpts of how those courts discussed it. The Library of Congress notes that while this feature gives a useful overview of how a case has been treated, it is not considered as authoritative as commercial citators.³ There are no warning flags, so you have to read the citing opinions and draw your own conclusion. The Free Law Project’s CourtListener platform has been developing AI-powered citation analysis, though the citator tool is still a work in progress.⁴

Free tools are useful for basic research and for spotting obvious problems, but they may miss recent opinions and won’t give you the at-a-glance signal that tells you a case has been overruled. If the stakes are high, verify with a commercial citator.

Reading the Signals

Commercial citators use color-coded flags, and the two major systems use different schemes. Confusing them is a common mistake.

KeyCite on Westlaw

Red flag: the case is no longer good law for at least one point of law it contains. This is the most serious warning and indicates the case has been reversed, overruled, or otherwise invalidated.⁵
Yellow flag: the case has some negative history but has not been reversed or overruled. Another court may have criticized, limited, or distinguished it.⁵
Blue-striped flag: the case has been appealed to a U.S. Court of Appeals or the U.S. Supreme Court. This is not a neutral-treatment signal; it means the case’s journey through the courts may not be finished.⁵

Shepard’s on LexisNexis

Red signal: strong negative treatment, such as being overruled or reversed.⁶
Orange signal: the continuing validity of the case has been questioned by a citing reference.⁶
Yellow signal: possible negative treatment, such as being limited or criticized, but not overruled.⁶
Green signal: positive treatment. The case has been followed or affirmed by later courts.⁶
Blue “A” signal: neutral treatment, such as being explained or cited without positive or negative commentary.⁶

KeyCite’s blue-striped flag and Shepard’s blue signal mean completely different things. Switching between platforms without recalibrating leads directly to misreading the results.

What a Flag Actually Tells You

A colored signal is a starting point, not an answer. A red flag on a case that addressed three separate legal issues might mean the case was overruled on only one of them. If the issue you care about was not the one that got knocked out, the case may still be good law for your purposes. Click through to the citing decision that triggered the flag and read what the later court actually said.

When you open a citing decision in a commercial citator, the software highlights the paragraphs discussing the original case. Look for the treatment language: did the later court say it was “overruling,” “reversing,” “questioning,” “distinguishing,” or “following” the earlier decision? Each tells you something different.

Distinguished Is Not Invalidated

A case that has been “distinguished” has not been knocked out. Distinguishing means a later court acknowledged the precedent but concluded its own facts were different enough that the earlier rule didn’t apply. This is normal legal reasoning, and a distinguished case remains fully valid for situations matching its original facts. Don’t panic over a yellow or orange signal until you read the treatment. Many cases accumulate negative signals over decades simply because courts in factually different disputes explained why the precedent didn’t control.

Partial Invalidity

Courts sometimes overrule a case on one ground while explicitly preserving its reasoning on others. When you see negative treatment, identify exactly which legal point was rejected and compare it to the point you need to cite. If they don’t overlap, the case remains good law for your argument. Citators typically identify the specific headnote or legal issue affected, which makes this comparison faster.

Recent Activity in Your Jurisdiction

After reviewing the flagged treatment, check the most recent citing decisions from courts in your jurisdiction. If a very recent decision from a high-level court criticizes the original case or signals a shift in legal thinking, the precedent may be in jeopardy even without a formal overruling. Courts sometimes telegraph that they are ready to abandon a precedent well before they officially do so.

A Valid Case Isn’t Always a Useful Case

Verifying that a case is still good law does not settle whether it binds the court hearing your dispute. Higher courts bind lower courts within their chain: a U.S. Supreme Court decision on a federal question binds every federal and state court, a federal circuit decision binds only the district courts within that circuit, and a state supreme court decision binds all lower courts in that state but has no authority elsewhere. A Fifth Circuit opinion in a Ninth Circuit case is persuasive at best. A perfectly valid opinion from the wrong court can still be ignored by the judge you are appearing before, so run the hierarchy check alongside the good-law check.

What Happens If You Cite Bad Law

The consequences range from embarrassing to career-threatening.

Duty of Candor

Under the ABA Model Rules of Professional Conduct, which most states have adopted in some form, lawyers have an affirmative duty of candor toward the court. Rule 3.3(a)(2) prohibits a lawyer from knowingly failing to disclose legal authority in the controlling jurisdiction that is directly adverse to the client’s position and not disclosed by opposing counsel.⁷ Citing a case as good law when you know, or should know through reasonable research, that it has been overruled implicates this duty.

Court-Imposed Sanctions

Federal Rule of Civil Procedure 11 requires that every legal argument in a filing be “warranted by existing law or by a nonfrivolous argument for extending, modifying, or reversing existing law.”⁸ A court that finds a violation can impose sanctions on the attorney, the law firm, or both, including orders to pay the opposing party’s reasonable expenses and attorney’s fees.

Separately, 28 U.S.C. § 1927 allows courts to hold attorneys personally liable for excess costs, expenses, and attorney’s fees when they “unreasonably and vexatiously” multiply proceedings.⁹ Building an argument on overruled precedent, forcing the opposing party to brief the issue and the court to address it, is exactly the conduct the statute targets.

Even without formal sanctions, citing bad law damages your credibility with the judge. Courts have long memories.

A Working Checklist

Confirm the citation. Verify the volume, reporter, and page number.
Identify the court and year. Determine where the case sits in the hierarchy and whether it would bind the court you are dealing with.
Isolate the specific legal point you need from the case.
Run a citator search. Enter the citation into Shepard’s, KeyCite, or a free equivalent. Check for red or orange signals first.
Read the negative treatment. If any flags appear, open the citing decisions and determine which legal point was affected. A flag on an unrelated issue does not kill the case for your purposes.
Check for legislative changes. Confirm no statute has been enacted that supersedes the court’s interpretation, especially if the case interpreted a statute rather than the Constitution.
Review recent activity. Look at the most recent citing decisions from courts in your jurisdiction to see whether the legal landscape is shifting.

The process takes minutes with a commercial citator and longer with free tools. Either way, it is cheaper than the consequences of getting it wrong.

1
Federal Judicial Center. Stare Decisis
2
LexisNexis. Purchase Lexis and Lexis+ – Pricing Plans for Law Firms
3
Library of Congress. Google Scholar – How To Find Free Case Law Online
4
Free Law Project. Building a Citator with AI, A Progress Report
5
Thomson Reuters. About KeyCite Status Flags
6
LexisNexis. Shepard’s Signal Indicators and Analysis Phrases
7
American Bar Association. Rule 3.3 – Candor Toward the Tribunal
8
Legal Information Institute. Federal Rules of Civil Procedure Rule 11 – Signing Pleadings, Motions, and Other Papers
9
Office of the Law Revision Counsel. United States Code Title 28 Section 1927