Akhil Reed Amar is the Sterling Professor of Law and Political Science at Yale and the author of America's Constitution: A Biography.

...The most powerful portents of the future are to be found in America’s existing state constitutions, the proverbial laboratories of American democracy. These 50 documents have converged to form a distinctly American model of governance—call it “American exceptionalism,” if you like. For example, unlike the regimes in various democratic countries around the world—England, Germany, France, Israel, India, Australia—almost all 50 states follow the same basic formula, featuring (1) ratified written constitutions, (2) bicameral legislatures, (3) chief executives who look remarkably like mini-presidents, and (4) robust bills of rights enforceable in ordinary courtrooms....