Of all the cases U.S. District Judge Michael P. McCuskey handled during the quarter-century he’s spent on the bench, one stands out. But it wasn’t until a year after issuing his ruling that he realized the true importance of his decision. In 2003, McCuskey ordered a new trial for Gordon “Randy” Steidl, a man who had spent 10 years on death row, convicted of killing two newlyweds in Paris, Ill., in 1986. Lawyer Michael B. Metnick and Northwestern University School of Law’s Center on …