Vice President Joe Biden greets supporters as one hands him a copy of the book "Joe Biden" after he addressed a grassroots rally, Tuesday, Aug. 21, 2012, in Minneapolis. (AP Photo/Jim M

 

              Vice President Joe Biden greets supporters as one hands him a copy of the book "Joe Biden" after he addressed a grassroots rally, Tuesday, Aug. 21, 2012, in Minneapolis. (AP Photo/Jim M
Vice President Joe Biden greets supporters as one hands him a copy of the book "Joe Biden" after he addressed a grassroots rally, Tuesday, Aug. 21, 2012, in Minneapolis. (AP Photo/Jim Mone)