(From DCist contributor Seth Thomas Pietras) Whoever said art and foreign policy don’t overlap? For the 54th season, the National Gallery of Art presents the world renowned A.W. Mellon Lectures in the Fine Arts, a series of six hour-long lectures taking place each Sunday beginning on April 10 going through May 15. This year’s lecturer will be Harvard professor Irene J. Winter, who will be presenting “Great Work”: Terms of Aesthetic Experience in Ancient Mesopotamia…