CHICAGO — Fashion and politics are seasonal and unpredictable, yet the two came together quite well here for the hometown designer Maria Pinto and Michelle Obama, whose first memorable bursts onto the national scene were often in Pinto creations. Remember the purple sheath Mrs. Obama wore the night of the fist bump heard round the world? The teal number at the Democratic National Convention? Or the red dress she wore to meet the Bushes on their way out of the White House? Maria Pinto all, designed right here where both women were born and raised and, over the course of...