State v. David Lynn Stewart
Background
- Officer stopped David Lynn Stewart for driving 26 mph in a residential area the officer believed had a 20 mph default limit; the officer relied on a repealed 1966 city ordinance rather than the statutory default of 35 mph.
- The only speed-limit signage that might have notified Stewart was on the outskirts of town and did not comply with statutory and federal requirements.
- The stop escalated into a DUI investigation; Stewart was charged with second-offense DUI and moved to suppress evidence obtained after the stop, arguing lack of reasonable suspicion.
- The magistrate found the officer mistakenly believed a 20 mph default applied but held the mistake was a reasonable mistake of law and denied suppression, relying on Heien.
- The district court affirmed, citing DeFillippo and treating the officer’s reliance on an existing (though repealed or unenforceable) ordinance as reasonable.
- On appeal, this Court reversed, holding that under Idaho precedent the Idaho Constitution does not recognize a good-faith mistake-of-law exception to the exclusionary rule; therefore the stop lacked lawful justification and evidence must be suppressed.
Issues
| Issue | Plaintiff's Argument | Defendant's Argument | Held |
|---|---|---|---|
| Whether an officer’s reasonable mistake of law can supply reasonable suspicion for a traffic stop | State: officer’s reliance on existing ordinance or objectively reasonable legal mistake justifies stop (good-faith exception) | Stewart: mistake of law cannot supply reasonable suspicion; stop invalid under Idaho Constitution | The Idaho Constitution does not permit a good-faith mistake-of-law exception; stop lacked lawful basis and evidence must be suppressed |
| Whether Idaho should follow federal decisions permitting good-faith mistakes (Heien/DeFillippo) | State: adopt Heien/DeFillippo and apply a good-faith exception | Stewart: Idaho precedent rejects such an exception; Guzman/Koivu control | Idaho precedent (Guzman, Koivu, Pettit) rejects adopting federal good-faith mistake-of-law exception; federal cases not controlling |
Key Cases Cited
- Heien v. North Carolina, 574 U.S. 54 (2014) (U.S. Supreme Court recognizing reasonable mistake of law can justify a stop under the Fourth Amendment)
- Michigan v. DeFillippo, 443 U.S. 31 (1979) (officer’s reliance on an ordinance later found invalid may be reasonable for Fourth Amendment purposes)
- State v. Pettit, 406 P.3d 370 (Idaho Ct. App. 2017) (Idaho Court of Appeals rejected a good-faith mistake-of-law exception under the Idaho Constitution)
- State v. Guzman, 842 P.2d 660 (Idaho 1992) (Idaho Supreme Court declined to limit Article I, §17 by adopting a good-faith exception)
- State v. Koivu, 272 P.3d 483 (Idaho 2012) (Idaho Supreme Court reaffirming greater protection under the Idaho Constitution than the federal Fourth Amendment)