Longtime U.S. Rep. Bobby Rush of Illinois, a onetime Black Panther with a dramatic rise in Illinois politics, announced Monday he won’t seek reelection after 15 terms representing his Chicago-area district.On Tuesday, he said in a speech at a Chicago church that he isn’t retiring from public service.“I will remain on the front lines,” he said.The Democrat, known for anti-violence activism and racial equity work, was first elected to Congress in 1992. He holds the distinction of being the only politician to win a race …