Jimmy Carter never fully regained Bill Clinton's trust after Mr. Carter's administration sent Cuban refugees to Arkansas in 1980. Mr. Clinton criticized George H. W. Bush for tanking the American economy. George W. Bush said Mr. Clinton's personal conduct in the White House undermined the dignity of the presidency. Barack Obama said the younger Mr. Bush's policies "likely created more terrorists around the world than it ever detained."
Now all five men – former presidents, their rivalries safely in the past – are rallying together in a poignant effort to aid the victims of Hurricanes Harvey and Irma.
Their televised plea for aid, called the "One America Appeal," aired during NFL football games Sunday and will be repeated during Monday night's games being played in Denver and Minnesota. The advertisement opens with Mr. Obama saying that "recently, our country has witnessed catastrophic devastation," followed by Mr. Carter saying that "across this great country, Americans have answered the call." Later, the younger Mr. Bush speaks of "that special calling that compels us, when others are down, to step up and do whatever it takes."
The television spot was a grace note in an era of great political tension. Four presidents in a row, beginning with Mr. Clinton, have faced ferocious opposition, with a crescendo coming with the ascension of Donald Trump to the White House. Mr. Trump did not appear in the ad, and it is almost certain that none of the five presidents who appeared voted for him.
Though it may seem that it takes a hurricane to take the wind out of bitter political rivalries, political tensions tend to dissipate once presidents leave office. The most bitter of opponents tend to find common cause with the only other figures who have the "glorious burden" – the phrase emerges repeatedly in accounts of the American presidency – in common.
This quality had its most vivid modern example seven years ago, when two consecutive former presidents created the Clinton Bush Haiti Fund to address the devastation of a Caribbean earthquake.
But the tradition dates to the very earliest years of the U.S. republic. John Adams and Thomas Jefferson had vastly different visions of the new country and, in effect, the early Democrats regarded Mr. Jefferson's presidency as a rebuke to the Adams administration. But as the years passed, the enmity dissipated and, beginning in 1812, the two were in constant communication. "You and I ought not to die before we have explained ourselves to each other," the second president wrote to the third. They both died on July 4, 1826 – exactly 50 years after the Declaration of Independence was approved by Congress.
Mr. Adams and Mr. Jefferson wrote less to confront a national emergency than to examine the threats and opportunities faced by a newly created country breaking new ground in political philosophy and structure. The respected historian C. Vann Woodward called the Adams-Jefferson correspondence "a major treasure of national literature." But national emergencies – wars, devastating storms, civil upheaval, important national challenges – often bring presidents together.
Herbert Hoover, reviled by Democrats and pilloried for decades as the father of the Depression, was mobilized by Harry Truman to address devastation and despair in postwar Europe and Asia. Years later, Mr. Truman, who later called on Mr. Hoover to head a commission to reorganize the government, received a letter from Mr. Hoover saying that "yours has been a friendship which has reached deeper into my life than you know."
In times of crisis, presidents almost always stand together. John Kennedy called on Dwight Eisenhower after both the Bay of Pigs fiasco in 1961 and the Cuban Missile Crisis in 1962. A picture of the two – Mr. Kennedy with hands in his suit-coat pocket, Mr. Eisenhower with hands clasped behind his back, walking solemnly together at Camp David – captures the gravity of the situation.
From time to time, former presidents are dispatched by sitting presidents to attend important funerals. In the dark of an October night, Richard Nixon, Gerald Ford and Mr. Carter met at Andrews Air Force Base to fly to Cairo to attend the funeral of Egyptian President Anwar Sadat. They did not appear together again until they joined 500 Washington dignitaries in a Navy-blue salute to Hyman Rickover, the admiral who was the father of the nuclear Navy – an event that then-senator Bob Dole of Kansas described as a meeting of "Hear-no-evil, see-no-evil … and evil."
The Clinton-Bush relationship has become a celebrated friendship, one so close that the Bush children sometimes refer to Mr. Clinton as the elder Bush's favourite son. In a letter to his children 18 years ago, Mr. Bush spoke of travelling to the funeral of Jordan's King Hussein with former presidents Clinton, Carter and Ford. He said that flight underlined Mr. Clinton's "great grasp of facts, apparently an in-depth knowledge on the issues."
In the advertisement for hurricane aid, Mr. Clinton said that "America is at her best when, against all odds, we come together and lift each other up." In truth, presidents in retirement lift each other up as much as they support each other. More than a decade ago, the elder Mr. Bush and Mr. Clinton shared an award. Shortly thereafter, Mr. Bush wrote his successor, "This note is to simply let you know that I so appreciated your words about our relationship, about our friendship. It was from your heart – and I hope you know I feel the same away."