Assume the Sept. 11 attacks had failed. Would U.S. troops be in Iraq? Who would be president? Would another attack have materialized? Where would we stand as a member of the community of nations?
John Heilemann, author of "The Power Grid" column for New York magazine; editor, What if 9/11 Never Happened?
Ron Suskind, Washington-based journalist; author of The One Percent Doctrine
Andrew Sullivan, conservative blogger, author of The Conservative Soul
Dahlia Lithwick, Slate judicial correspondent