I am standing in front of two full-length portraits, each just over 200 centimeters tall. The one on the left is a gray-scale screen print; in it, a man in a billowy shirt with a popped collar, jeans, and cowboy boots has emerged from the void to draw a revolver from the holster at his hip, which he points at the viewer. The one on the right is painted in thick, dark oils; it shows a man in a black three-piece suit and polka dot tie, his hands in his trouser pockets, standing in his study, before wall-to-wall, floor-to-ceiling bookshelves and a desk covered in a red, tasseled table cloth, on which the viewer can make out two candlesticks and a set of miscellaneous papers. The subject of the first painting is Elvis Presley. The subject of the second: Vladimir Lenin. These two portraits—Andy Warhol’s Elvis Presley (Single Elvis) (1964) and Dmitriy Nalbandyan’s Lenin (1980–82) respectively—flank the entrance of “The Cool and the Cold: Painting in the USA and the USSR 1960-1990,” a selection of over 125 pieces from the collection of the late chocolate manufacturer and art historian Peter Ludwig and his wife Irene, now on view at the Gropius …