Who is Marwan Barghouti and why are so many calling for his release?

One of the names floated as a potential leader of a future Palestinian state is Marwan Barghouti . A 67 year old currently in Israeli jail following convictions including for murder and membership of a terrorist organisation. But who is Barghouti and why are so many calling for his release? Pat asked Fawaz Gerges, Professor of International Relations, London School of Economics and Political Science.