PlayPennsylvania - the make or break state
Published: Saturday, 3 May 2008, 2:26PM
After a six-week break in voting in the Democratic presidential battle, ITV News Washington correspondent John Irvine explains in an exclusive online report just how significant the fight for Pennsylvania is.
Barack Obama and Hillary Clinton square off on Tuesday in the biggest state remaining on the Democratic party's nominating calendar.
Nine contests are left after Pennsylvania, and Mrs Clinton is struggling to gain ground on Mr Obama in delegates to the August nominating convention and the popular vote won during the primary battle.
Mrs Clinton, a New York senator, has resisted calls to drop out of the race and allow Mr Obama to concentrate on the match-up with Republican John McCain in November's presidential election.