An impeachment witness against president Joe Biden is suing former White House staffer Cassidy Hutchinson for defamation. The complaint filed in Washington, D.C., by attorneys for Tony Bobulinski, a former business associate of Hunter Biden, claims Hutchinson insinuated in her book “Enough” that he and then-White House chief of staff Mark Meadows were “involved in some sort of nefarious dealings” when they briefly huddled at a Donald Trump campaign rally on Nov. 1, 2020, in Georgia. “[Hutchinson’s] defamatory statements about Mr. Bobulinski were knowingly and recklessly false,” the complaint s…