A new online tool called Constitute compares 189 constitutions, tagging them on 300-plus themes.
There have been intermittent calls, down the years, for a switch to a parliamentary system; and, after the second world war, American constitutional experts pressed parliamentary constitutions on Japan, West Germany and Italy.
All these changes require a new constitutional order, making it vital that Arab countries get their constitutions right.The record so far looks unpromising.
Many African presidents have tried to stay in power by rewriting their countries' constitutions to lose the limits on presidential terms.
Enduring constitutions nevertheless require three essential things: first, a general recognition that there is a problem that needs solving; second, a shared willingness to produce a shared outcome; and, third, a degree of readiness and goodwill to make that outcome a lasting settlement.
At all levels, local, national, regional and global, new constitutions for political institutions need to be considered, as in Iceland or in some Latin American countries.
Governments that operate under constitutions protecting freedom of expression have to inquire, urgently, whether that freedom exists when everything is spied on, monitored, listened to.
It rejected a Louisiana law which requires would-be voters to interpret any section of the federal or state constitutions and cleared the way for the federal government to bring a suit against the State of Mississippi which has a similar literacy requirement.
Two decades ago, fewer than a third of Americans opposed the policy; today, the country is evenly split on the question, and the eight states with racial-preference bans in their constitutions are the vanguard of a movement to slow the practice in America's public universities.
To avoid this, the current vogue is for family constitutions, often drawn up by expensive lawyers in London.
The presidents of Rwanda and the Democratic Republic of Congo have recently contemplated changing constitutions to give themselves extra time in office.
