How far can passion carry Bernie Sanders?
DES MOINES, Iowa - Sheila Campbell was not a natural door-to-door campaigner. The Democrat from Urbandale, Iowa, canvassed for one day in 2008 for Barack Obama and hated it so much that she didn't do it again.
Until this year.
Since early April, Campbell, an office manager for a neuropsychology clinic, has been knocking on doors and talking up Sen. Bernie Sanders to Democrats, Republicans, independents - to anybody who would listen. The day the Vermont senator had a heart attack in October, she went to a campaign office to volunteer more hours.
"This man is putting everything on the line for us," Campbell said of Sanders. "Whatever I can do, if they call, if they ask, I say 'yes.'"
With less than three months until the Democratic presidential caucuses in Iowa, the
