The new legislation was meant in part to reduce the frequency of youthful drinking and driving. In the year when the law was implemented, half of Florida's 19-year-olds could drink legally; the other half could not. In this paper we analyze self-report data from a sample of these 19-year-olds, examining differences in drinking behaviors and in drinking and driving among legal and illegal drinkers. We find no differences in self-reported drinking or in drinking and driving between the two groups. This finding suggests that the law may not have had the effect that was intended. The two groups differ, however, in the social contexts of drinking, in how they obtain alcohol, and in attitudes about the legitimacy of laws. These differences highlight the importance of understanding unanticipated, potentially negative consequences of legal changes. 5 tables, 1 figure, 38 references. (Publisher abstract)