MIDDLEBURY On Tuesday, Nov. 18, at 7:30 p.m., Middlebury College President Emeritus and Professor John McCardell will give a talk titled The 21 Year-Old Drinking Age: Mend It or End It? This lecture is part of The Forum at 51 Main, a new series designed to bring together the town and college in the exploration of important ideas and pressing issues in a convivial setting. The talk will take place at 51 Main, located on Main Street in downtown Middlebury. McCardell taught at Middlebury since 1976, and he served as its president from 1991 to 2004. In 2006, McCardell founded Choose Responsibility, a nonprofit organization designed to debate the effects of the 21-year-old drinking age. More recently, he has spearheaded the Amethyst Initiative, a call by more than 130 college and university presidents for renewed discussion about the implications of the current national drinking age.