Eighteenth Amendment to the United States Constitution
The third clause gave seven years as the time period for the states to ratify the amendment. This is the first amendment to have a limit on the time in which it was to be ratified. If it was not ratified by the required number of states in that time period, the amendment would not go into effect. Article Five of the United States Constitution requires an amendment be passed by three-quarters of the states. (36 out of the 48 states at that time.)