The Franks Motion: Challenging a Search Warrant Affidavit

Where It Comes From

Normally, a court reviewing a search warrant looks only at the "four corners" of the affidavit and presumes it's truthful. Franks v. Delaware, 438 U.S. 154 (1978), created a narrow exception: a defendant can go behind the affidavit and challenge its veracity — but only by meeting a high threshold first. This is the mechanism behind a motion to suppress when the problem is not how the warrant was executed, but how it was obtained.

The Substantial Preliminary Showing

To earn a Franks hearing, the defense must make a substantial preliminary showing of three things:

1. The warrant affidavit contained a false statement (or omitted a material fact);
2. The affiant made the false statement, or omitted the fact, knowingly and intentionally, or with reckless disregard for the truth (not just by innocent mistake); and
3. The false statement or omission was necessary to the finding of probable cause — meaning that without it, the warrant would not have issued.

This is not a low bar. The showing requires more than allegations — typically an offer of proof through affidavits or other reliable evidence. Courts have repeatedly noted these elements are hard to prove and that Franks hearings are, in practice, rarely granted. An honest assessment of whether the facts can meet this standard is part of deciding whether to bring the motion.

Falsehoods and Omissions Both Count

A Franks challenge isn't limited to affirmatively false statements. It also reaches material omissions — facts the affiant left out that, had they been included, would have undercut probable cause. An officer who omits information that cuts against the warrant can be challenged the same way as one who includes something false.

What Happens If It Succeeds

If the court grants a hearing and the defense proves the falsehood or omission by a preponderance of the evidence, the court sets aside the false material (or inserts the omitted material) and re-examines the affidavit. The question then becomes whether what remains still establishes probable cause. If it does, the warrant stands. If it does not, the warrant is void and the evidence obtained under it is suppressed — which can be case-ending when the search produced the State's central evidence.

How It Fits the Bigger Picture

A Franks motion is one specific way to attack a search warrant. Other challenges go to whether the warrant was supported by probable cause on its face, whether it was overbroad, or whether it was properly executed. A careful defense reviews the warrant and its affidavit for all of these, because suppressing the fruits of a search is often the difference between a strong case against the client and no case at all.