James Allen Johnson was convicted of aggravated assault and obstruction after using a knife while resisting an officer. The Court of Appeals of Georgia affirmed the aggravated-assault conviction but reversed the misdemeanor obstruction conviction because the State had not proved that the officer was acting within the lawful scope of his duties. The court held that Johnson’s use of force could be found disproportionate to the force used to detain him, so his common-law right to resist did not require reversal of the aggravated-assault conviction.