The federal courts in Chicago operated at full strength today, but some prosecutors were already feeling the impact of the shutdown triggered by Congress’ failure to fund the government. Assistant U.S. attorneys who try criminal cases were exempt from furloughs that went into effect at 11:01 p.m. Monday — just after midnight in Washington, D.C. — as lawmakers remained deadlocked on a bill to keep the government functioning. However, most of the 25 to 30 assistant U.S. attorneys who handle civil …