PITTSBURGH, Sept. 28 -- Before Sept. 11, 2001, all Kristen Breitweiser wanted in the way of worldly responsibility was to tend to her garden and care for her infant daughter, Caroline. "After watching my husband get murdered on live worldwide television," she said, everything changed. On Tuesday, the 33-year-old New Jersey widow was stumping in swing states with Democratic vice presidential candidate John Edwards for the second day in a row. [snip]She fought back a fear of flying born out of the World Trade Center disaster and overcame her jitters about public speaking to become a blunt instrument of...