Was the Final Solution gradual or predetermined?

Our speaker is Richard Breitman who is an Emeritus Professor of History at American University and the author of a new book entitled Calculated Restraint: What Allied Leaders Said About the Holocaust. I want to learn from Richard about whether the allies should have bombed the rail lines to the concentration camps and if Roosevelt and Churchill should have said more to warn the Jews of Europe to the Holocaust so that the Jews could have gone into hiding.