CAMPAIGN SUPPORTERS First Lady Michelle Obama and Dr. Jill Biden, wife of Vice President Joe Biden, lead applause for Army Gen. Martin E. Dempsey, chairman of the Joint Chiefs of Staff, and Tom Brokaw, television correspondent and author, as they participate in an event to mark the first year of "Joining Forces," a national campaign to support military families, at the White House, April 11, 2012. SHARE: Download: Full Size (0.07 MB) Credit: VIRIN: 640008-L-KJR51-735.jpg Photo Gallery