Rhode Island Democratic Rep. Patrick Kennedy, the last member of his illustrious family currently serving in Congress, will announce on Friday that he is retiring, according to Democratic insiders. Kennedy, 42, was first elected to Congress in 1994. He did a stint as chairman of the Democratic Congressional Campaign Committee in the 1999-2000 cycle but has not served in the House Democratic leadership beyond that. His congressional tenure was marked by repeated substance abuse problems, including a drunk-driving incident in 2006. He entered a rehab facility at that time and again in 2009. Sen. Ted Kennedy (D-Mass.), the congressman's father,...