Anyone familiar with New York Fashion Week knows that much of the pomp and circumstance (with all due respect to Alexander Wang and his biannual gas-station soiree) centers around the Marc Jacobs runway show, and which celebrities are watching it from row one. Enough hype, in fact, to perhaps overshadow Jacobs’s actual designs, and specifically his menswear. The designer’s diffusion line, Marc by Marc Jacobs, set the bar a decade ago for all little-brother and -sister offshoots produced by major fashion houses. At a time when “diffusion” usually suggests cheaper fabrics and outsourced production, Marc by Marc has maintained a rigidly high standard. A perfect example is this fully-lined wool glen plaid blazer. It strikes a professorial note with suede elbow patches, leather buttons, and functioning button cuffs. All produced in the U.S.A. Pretty impressive for a younger brother.