WASHINGTON (AP) - President Barack Obama is addressing one of his key constituencies - organized labor - on Monday as union members gather to celebrate the holiday named for their movement. As Obama prepares for a critical speech Wednesday to Congress and the nation about his efforts to overhaul health care, a supportive audience at the AFL-CIO's annual Labor Day picnic in Cincinnati should provide welcome relief from the highly charged partisan atmosphere surrounding the issue. Besides addressing health care, Obama will tell the assembled union members he has named Ron Bloom as senior counselor for manufacturing policy. Bloom has...