An entire generation has gone by since the US last saw this tableau of American history: every living president together at the White House.

Consider it time for a reunion among the members of one of the world's most elite clubs, plus the one man about to join it - Barack Obama.

Picking up on an idea from Obama, President George W. Bush yesterday was hosting a lunch for the incoming president and the three living former presidents: Bill Clinton, George H.W. Bush and Jimmy Carter. It will be the first time all the living presidents have gathered at the White House since 1981.