Good Faith Exception

The good faith exception is a rule that lets prosecutors keep evidence even when the warrant used to obtain it turned out to be defective. The reasoning is that if the police were honestly relying on a warrant a judge had signed, suppressing the evidence would not actually deter police misconduct. The exception is one of the most important — and most contested — limits on the Fourth Amendment‘s exclusionary rule.

How the Good Faith Exception Works in California

The good faith exception comes from the U.S. Supreme Court’s decision in United States v. Leon, which held that evidence obtained pursuant to a search warrant later found to lack probable cause should not be suppressed when the executing officers acted in objectively reasonable reliance on the warrant. The exception applies in California because Proposition 8 incorporated federal Fourth Amendment standards into California search-and-seizure law. California courts apply Leon and its progeny through Penal Code § 1538.5 litigation.

The exception is not unlimited. Leon itself identified four situations where good faith does not apply: when the magistrate was misled by an affidavit the officer knew or should have known contained false information; when the magistrate wholly abandoned their judicial role; when the affidavit was so lacking in probable cause that no reasonable officer could rely on it; and when the warrant was so facially deficient — for example, by failing to particularize the place to be searched or things to be seized — that the executing officer could not reasonably presume it valid.

The exception has been extended in important ways. In Herring v. United States, the Supreme Court applied good faith reasoning to evidence obtained when an officer reasonably relied on incorrect information in a police database. In Davis v. United States, the Court applied it to searches conducted in reasonable reliance on then-binding appellate precedent that was later overruled. California courts have applied these extensions in their own decisions, and the exception now reaches well beyond the original warrant context.

There are limits the defense can exploit. Good faith does not apply to warrantless searches (other than database errors), to searches that exceed the scope of a warrant, or to consent searches where the consent was not voluntary. It also does not apply when officers themselves contributed to the problem — by misleading the magistrate, by drafting an affidavit so thin that no reasonable officer could rely on it, or by executing a warrant that was so vague it amounted to a general warrant. Identifying when the exception does and does not apply is one of the most important parts of California Fourth Amendment litigation.

Why the Good Faith Exception Matters to Your Defense

The good faith exception is often the single biggest obstacle to a successful suppression motion in a warrant case. A skilled criminal defense attorney has to be ready not just to challenge the warrant itself, but to defeat the prosecution’s good faith argument. This means scrutinizing every detail of the affidavit, the warrant, and the execution — looking for signs that the officer misled the magistrate, that probable cause was so absent that reliance was unreasonable, or that the warrant was facially defective.

Franks litigation is one of the most powerful tools against good faith. Under Franks v. Delaware and California cases applying it, the defense can challenge a warrant by showing that the affidavit contained false statements or material omissions made knowingly or with reckless disregard for the truth. If the falsehoods are essential to probable cause, the warrant fails — and good faith generally does not protect officers who misled the magistrate. Building a Franks claim takes careful investigation, but it can defeat the exception entirely.

The exception also matters in cases involving database errors and overruled precedent. Defense attorneys who track the most recent California and federal Fourth Amendment cases can identify situations where the law has shifted and the prosecution may try to invoke Davis-style good faith. Pushing back on those arguments — and litigating the precise scope of officer reliance — is the kind of detailed criminal defense work that decides cases.

Related Legal Terms

The good faith exception is a key carve-out from the exclusionary rule and is litigated within the broader framework of the Fourth Amendment, search warrants, and probable cause. It is a constant feature of suppression motion practice in our DUI defense, drug crimes defense, and weapons charges work.

Facing Charges Where This Applies?

If your case involved a search warrant — or police claim to have acted in good faith on bad information — the application of this exception may decide whether key evidence comes in. Attorney Chris Nalchadjian offers free, confidential consultations 24/7. Call KN Law Firm at (888) 950-0011.