Outdated laws in America can still be enforced because a statute stays valid until a legislature formally repeals it, and repeal takes the same work as passing a new law. That is why 19th-century morality rules, Sunday commerce bans, and a federal obscenity statute from the Grant administration still sit in the official codes. Most are blocked in practice by Supreme Court rulings, prosecutorial discretion, or basic due process. A few, including one 1986 privacy law, still cause real harm.
Sunday Blue Laws
Blue laws are the outdated rules you are most likely to run into. They started as religious observance of the Sabbath, and they survive today as secular worker-protection measures. About a dozen states still prohibit car dealerships from opening on Sundays or require them to close at least one weekend day, and a similar number restrict Sunday liquor sales at the state level.
The Supreme Court upheld these restrictions in McGowan v. Maryland in 1961, finding that Sunday closing laws do not violate the Establishment Clause so long as they serve a secular purpose like providing a uniform day of rest.1Justia. McGowan v. Maryland, 366 U.S. 420 (1961) That ruling has shielded blue laws from First Amendment challenges for more than sixty years, and they are actively enforced. If you want to test-drive a car on a Sunday afternoon in one of those states, you are out of luck.
The trend is toward loosening them. Sixteen states have opened up Sunday spirits sales since 2002. Car-dealership bans have proved stickier, partly because dealer trade associations in some areas support the mandatory day off to prevent competitors from forcing weekend hours.
Cohabitation and Adultery Statutes
At least five states still technically criminalize cohabitation, and several others maintain adultery statutes, one of which classifies the offense as a felony. The written penalties range from modest fines to six months in county jail.
In practice, these laws collapsed in 2003 when the Supreme Court decided Lawrence v. Texas. The Court held that criminalizing consensual intimate conduct between adults violates the Due Process Clause and recognized “a realm of personal liberty which the government may not enter.”2Justia. Lawrence v. Texas, 539 U.S. 558 (2003) The case specifically struck down a sodomy statute, but its reasoning extends to private consensual behavior generally, which gutted cohabitation and fornication statutes nationwide.
The text stays in the codes because legislators avoid the political risk of voting to “legalize” adultery, even when the statute is a dead letter. That lingering language creates genuine confusion. Someone reading their state’s criminal code online might believe they are breaking the law by living with a partner, and these provisions occasionally surface in custody disputes or divorce proceedings as rhetorical ammunition. No modern court would sustain a criminal charge under one.
The Comstock Act
The Comstock Act, originally passed in 1873, is still codified at 18 U.S.C. ยง 1461. It makes it a federal crime to mail anything obscene or indecent, and it sweeps in any material related to producing an abortion, or even information about where to obtain one.3Office of the Law Revision Counsel. 18 USC 1461 – Mailing Obscene or Crime-Inciting Matter A first violation carries up to five years in federal prison. Subsequent offenses double the maximum to ten years.
Courts narrowed the Comstock Act through 20th-century First Amendment rulings that raised the bar for what qualifies as obscene, and the abortion-related provisions were widely considered dormant after Roe v. Wade in 1973. Congress never repealed or amended the language, so the words still sit in the federal code exactly as they were written. The statute is the clearest example of how a seemingly dead law can regain relevance when the legal or political landscape shifts around it.
Horse-Era Municipal Rules
Municipal codes across the country still contain regulations drafted when horses dominated city streets: hitching-post requirements outside public buildings, rules about how far livestock must stay from schools and churches, and tethering ordinances for downtown areas. Some jurisdictions also retain early automobile-era rules designed to keep cars from spooking horses, including the famous requirement that someone walk ahead of a steam-powered vehicle waving a red flag.
Violating these ordinances carries a small fine on paper. Enforcement is nonexistent because the circumstances they describe no longer occur, and no constituency is pushing for repeal. If you ever did receive a citation under one, the defenses discussed below would almost certainly end the case.
The Electronic Communications Privacy Act
Not every outdated law is harmless. The Electronic Communications Privacy Act of 1986 governs how the government accesses your digital information, and it was written before the World Wide Web existed. Under its Stored Communications Act provisions, the government needs a warrant to reach emails and other electronic communications stored for 180 days or less. For anything older than 180 days, it can use a subpoena or court order requiring far less justification than probable cause.4Office of the Law Revision Counsel. 18 USC 2703 – Required Disclosure of Customer Communications or Records
In 1986, that distinction was at least defensible. Electronic storage was expensive, and messages lingering on a server for six months were assumed to be abandoned. Today, virtually everyone keeps years of email, photos, financial records, and personal documents in the cloud indefinitely. The 180-day line means the government can reach deeply personal information without meeting the Fourth Amendment standard that would apply to a physical search of your desk drawer.
The Supreme Court has started pushing back. In Carpenter v. United States, the Court held that obtaining historical cell-site location records from a wireless carrier counts as a Fourth Amendment search requiring a warrant, even though a third party holds the records.5Justia. Carpenter v. United States, 585 U.S. ___ (2018) That signaled stronger protection for digital records than ECPA provides. Congress has not updated the statute to match. ECPA is the clearest example of an outdated law causing ongoing harm, not because anyone forgot about it but because legislative gridlock has stalled modernization for nearly four decades.
Why These Laws Stay on the Books
Killing a law is as procedurally demanding as passing one. A repeal bill has to be introduced, assigned to a committee, debated, voted through both chambers, and signed by a governor or the president. Legislators have limited floor time and strong incentives to spend it on current policy. Cleaning up a dead cohabitation statute wins no votes and invites a misleading attack ad about “legalizing sin.” The old text accumulates.
Some states run law revision commissions that identify obsolete statutes and recommend repeal, and where those bodies exist and are funded they can clear out thousands of code sections. Most jurisdictions lack any dedicated cleanup mechanism, so nobody owns the problem.
There is a doctrine called desuetude that would seem to fit: the idea that long-sustained non-enforcement should eventually invalidate a law. American courts have consistently refused to adopt it. A statute cannot be repealed by failure to prosecute. Only a legislature can formally remove a law from the books, so an 1875 statute carries the same formal legal weight as one signed last year.
Defenses If Someone Actually Tries to Enforce One
On rare occasions a prosecutor or local official does dust off an old statute, sometimes from genuine conviction and sometimes as leverage in a broader dispute. Defendants have real defenses even though desuetude is off the table.
The most common challenge is due process notice. If a law has gone unenforced long enough that a reasonable person would have no idea it existed, prosecuting someone under it raises serious fairness problems. The question is not whether the statute is technically valid but whether the defendant had adequate notice that the conduct was criminal. A law ignored for a century, with widespread community acceptance of the prohibited behavior, creates exactly the kind of notice failure due process is meant to prevent.
Prosecutorial discretion is a second practical check. The American Bar Association lists “prolonged non-enforcement of a statute, with community acquiescence” as a factor prosecutors should weigh before filing charges. Most prosecutors have bigger problems than someone who failed to maintain a hitching post, and the public reaction to such a case tends to be swift and unflattering.
For laws reaching private conduct between consenting adults, Lawrence v. Texas is a constitutional wall. Any attempt to enforce a cohabitation or morality statute runs directly into the Due Process Clause, and courts would almost certainly throw out the charges on that basis.2Justia. Lawrence v. Texas, 539 U.S. 558 (2003) The statute may still be printed in the code. It has no teeth.