Complex sentence: During the 1856 presidential election, Carroll supported and campaigned on behalf of Fillmore, the South American/Whig candidate, writing many articles and pamphlets and touring the Northeast on his behalf.
Split into simpler sentences: During the 1856 presidential election, Carroll supported and campaigned on behalf of Fillmore, the Southern Whig candidate. Carroll wrote many articles and pamphlets and toured the Northeast on his behalf.