For 80 years, American Presidents have been speaking to the National Scout Jamboree, a gathering of tens of thousands of youngsters from around the world eager to absorb the ideas of service, citizenship and global diplomacy.

In keeping with the Scouts' traditions, all eight presidents and surrogates who have represented them have stayed far, far away from partisan politics.

Franklin Delano Roosevelt used the occasion to talk about good citizenship. Harry S. Truman extolled fellowship: “When you work and live together, and exchange ideas around the campfire, you get to know what the other fellow is like,” he said.

President Dwight D. Eisenhower invoked the “bonds of common purpose and common ideals.” And President George H.W. Bush spoke of “serving others.”

For a brief moment at this year's jamboree in West Virgina, President Donald Trump indicated that he would follow that tradition - sort of.

“Who the hell wants to speak about politics when I'm in front of the Boy Scouts?” he said.

Then, standing before all 40,000 of them, he bragged about the “record” crowd size, bashed President Barack Obama, criticised the “fake media” and trashed Hillary Clinton's presidential campaign. In the 35-minute speech, the President threatened to fire his health and human services secretary if he couldn't persuade members of Congress to vote for the Republican healthcare bill.

At one point, he told a rambling story about a conversation he had at a New York cocktail party with a once-successful home builder who “lost his momentum.” The lesson, apparently: “You have to know whether or not you continue to have the momentum. And if you don't have it, that's okay.”

Throughout the address, Trump dropped in praise for “the moms and the dads and troop leaders” and thanked the Scouts for upholding “the sacred values of our nation.”

It was yet another example of Trump ignoring the custom that past presidents have dutifully observed in such public ceremonies. In his first full day in office, Trump bucked tradition at the CIA when he delivered a campaign-style speech in front of a memorial wall for fallen agency employees. In May, he used a commencement ceremony at the Coast Guard Academy to lament that he has been treated “more unfairly” than any other politician in history. And so it was at this year's jamboree. Trump, who promised to be different from all the rest, was indeed just that, talking to the Scouts in a way no president ever has.

Here, by way of illustration, is an abbreviated history of American presidents and their encounters with the Boy Scouts jamboree.

President Franklin Delano Roosevelt (1935 and 1937)

Roosevelt, once called the “greatest friend Scouting ever had in the White House,” helped secure support from federal and local officials to host the inaugural Scout Jamboree in Washington, DC, in 1935. There were plans to line the scouts along Constitution Avenue and throw a party on the White House lawn. But the gathering was derailed when a polio outbreak near the nation's capital put the Scouts at too great a risk.

The President, who said he had looked forward to the jamboree for more than a year, addressed the Boy Scouts by radio instead.

Roosevelt said that Boy Scouts, present and former, “constitute a very real part of our American citizenship” that relies on unselfishness and cooperative attitudes. “Scouting revolves around not the mere theory of service to others but the habit of service to others,” he said.

The young boys should be engaged in civic affairs in their home communities, even before they can legally vote, Roosevelt said, praising “the many contributions that individual Scouts and Scout organizations have made to the relief of suffering, the relief of the needy, to the maintenance of good order and good health, and to the furtherance of good citizenship and good government.”

The great outdoors, he added, are to be loved and understood, and he reminded the boys of their Scout Motto to always “be prepared.”

“When you go out into life, you have come to understand that the individual in your community who always says 'I can't' or 'I won't' or 'I don't,' the individual who by inaction or by opposition slows up honest, practical, far-seeing community effort, is the fellow who is holding back civilization and holding back the objectives of the Constitution of the United States,” Roosevelt said.

“We need more Scouts,” he added. “The more the better. For the record shows that taking it by and large, boys trained as Scouts make good citizens.”

Two years later, Roosevelt joined the Scouts in DC, where they found his face on the first page of the Jamboree Journal with a greeting and plug for good citizenship, according to Scouting Magazine.

The former president toured the camp site, took 12 Eagle Scouts to the Major League Baseball All-Star Game and visited with a group from New York that had built a large replica of the Roosevelt family home, reported the magazine.

President Harry S. Truman (1950)

This jamboree was on July Fourth at Valley Forge, Pennsylvania, where General George Washington brought his army in the winter of 1777. Truman noted the soldiers' struggles - the bitter cold, lack of food, poor shelter and tattered clothing - to make a greater point about perseverance.

“But the men of Washington's army stuck it out,” Truman said. “They stuck it out because they had a fierce belief in the cause of freedom for which they were fighting. And because of that belief, they won.”

Truman's speech morphed into a lesson on international diplomacy, world peace and freedom for all. He listed off the many states and foreign countries from which Scouts had come to attend the jamboree.

“When you work and live together, and exchange ideas around the campfire, you get to know what the other fellow is like,” Truman said. “That is the first step toward settling world problems in a spirit of give and take, instead of fighting about them.”

The “Scout movement,” the former president said, is “good training” for nation building work across the globe. Truman took shots at the dictators Adolf Hitler and Benito Mussolini, then shifted his criticism to “Communist-dominated countries” that are giving children “a completely distorted picture of the world.”

He said:

“'The great tragedy of our times is that there are movements in the world that deny this fundamental ideal of human brotherhood. These movements have devoted themselves to preaching distrust between nations. They have made a religion of hate. They have tried to turn the peoples of the earth against one another - to create a gulf between different peoples that fellowship cannot bridge. As a part of this effort, they have tried to poison the minds of the young people.'”

The United States, Truman said, “is striving to build a world in which men will live as good neighbours and work for the good of all.” He said he hoped all Boy Scouts in attendance would take home an understanding of “human brotherhood” and “work for freedom and peace with the same burning faith that inspired the men of George Washington's army here at Valley Forge.”

President Dwight D. Eisenhower and Vice President Richard Nixon (1953, 1957 and 1960)

Eisenhower, who visited the jamboree in 1950, was unable to physically attend three years later as president but recorded a video message for the Scouts.

Like Truman, he noted the importance of rubbing elbows with fellow Scouts of different ethnic and cultural backgrounds. He predicted they would leave the gathering with “a new sense of the vastness and complexities of this nation and of the world.”

“I am confident that, in meeting and talking with your fellow Scouts, you will gain a renewed awareness of the need for cooperating - working together - in our country and in the world,” Eisenhower said. “Bonds of common purpose and common ideals can unite people, even when they come from the most distant and diverse places.”

Nixon spoke on Eisenhower's behalf in 1957 and Eisenhower delivered another speech three years later, but the transcripts were not readily available.

President Lyndon B. Johnson (1964)

Johnson, eight months into his first presidential term, built his address around the theme of the great “American idea,” encouraging the Scouts to remember the country's history as they work to better its future.

“This country of ours is a community built on an idea,” Johnson said. “Its history is the history of an idea. And its future will be bright only so long as you are faithful to that idea.”

He used their location - again at Valley Forge - to speak of the “idea and a dream” that gave the troops at Valley Forge “the strength to survive the winter.”

The “American idea,” Johnson said, was what the founders outlined in the Constitution: a government of and by the people, religious freedom and the right to speak without censorship.

“As a result, in America we have a Government which exists to protect the freedom and enlarge the opportunities of every citizen,” he said. “That Government is not to be feared or to be attacked. It is to be helped as long as it serves the country well, and it is to be changed when it neglects its duty.”

He touched on the otherness of the Beltway, and how Washington, DC, “must often seem difficult to understand.” But he reminded the Scouts that government is made of people like them, all over the country, with different home towns and backgrounds and life experiences. Johnson said he was certain a number of them would even grow up to serve their country, too.

“These ideas are as old as your country, but they are not old-fashioned ideas,” he said. “They are as alive and as vital as America itself. I have no doubt that if you remain true to them, you will remember these days of Scouting as only the beginning of a lifetime of useful service to America.”

Looking at the Scouts' “smiling, optimistic” faces, Johnson said with a hint of melodrama, “will give me strength that I need in the lonely hours that I spend in attempting to lead this great Nation.”

First Lady Nancy Reagan on behalf of President Ronald Reagan (1985)

President Reagan was in the hospital recovering from cancer surgery during the 1985 jamboree, so first lady Nancy Reagan addressed the crowd in his place, delivering a forceful speech about the perils of drug abuse. Reagan told the Scouts they were “what is most positive about America's young people today.”

“No one can use drugs and remain a true Boy Scout,” she said. “Drug-free is the best way and the only way to live. Boy Scouts can help save their generation from drugs.”

President George H.W. Bush (1989)

In his remarks at the 1989 jamboree, the elder President Bush touched on everything from the American colonists to salmon fishing to moon outposts. He raved about the potential for a new generation in space exploration and encouraged Scouts to keep a “spirit of wonder, of discovery and adventure” that would draw them to “far distant worlds.”

Like Nancy Reagan before him, Bush devoted a significant part of his speech to the war on drugs, one of the signature domestic policies of his presidency. Bush listed drug abuse as one of his “five unacceptables,” which also included illiteracy, unemployment, child abuse and hunger.

Citing the rise of crack and cocaine, he called on the Scouts to lead by example and refuse “any illegal drug.” He recalled a story about a boy named Ryan Shafer who started using drugs at age 12 and died four years later after becoming a “stranger to his parents and classmates.” Bush implored the Scouts to ask themselves if they knew someone like Ryan and whether they had done everything in their power to help.

“By actively engaging in the lives of others,” Bush said, “you are demonstrating a central theme, a central idea of this administration: that from now on in America, any definition of a successful life must include serving others.”

President Bill Clinton (1997)

When Clinton spoke to the Scouts in 1997, it was the 60th anniversary of the first jamboree, and Clinton seemed to revel in the occasion.

With classic Clintonian flair, he name-checked no fewer than a dozen attendees and associates, gave a shout-out to the Arkansas flags flying in the background, recounted his days as a Scout at Ramble Elementary School, then told a more recent story about a scoutmaster from Missouri who tackled a man who had tried to run down pedestrians at a park in Washington (“I don't know if there's a Scout merit badge for tackling dangerous people who are violating the law,” he said, “but if there is one, I think he ought to get it.”)

The bulk of his speech focused on people doing “good turns” for one another - a core practice of the Scouts, he said.

“If every young person in America would give back to their community in the way you do, just imagine what we could do,” he said. “Imagine how many fewer problems we could have. So many times I have wished that every young person in America had the chance to be a part of Scouting. And tonight I see why, more clearly than ever. So I hope you'll go home and help others to serve and learn the joy that you share by the service you do.”

Clinton closed with a quote from French writer Alexis de Tocqueville: “America is great because America is good.”

President George W. Bush (2001 and 2005)

The younger President Bush addressed Scouts directly on two occasions, the first in 2001 during the early days of his presidency. Bad weather had prevented him from appearing in person that year, but he offered some words of advice in a videotaped message, putting his “compassionate conservative” image on full display.

Bush spoke of the Scouts' “heartland” values that “build strong families, strong communities and strong character.”

“The goodness of a person and of the society he or she lives in often comes down to very simple things,” he said. “Every society depends on trust and loyalty, on courtesy and kindness, on bravery and reverence. These are the values of Scouting and these are the values of America.”

Four years later, Bush spoke for more than 17 minutes, drawing multiple rounds of applause - and even a few laughs - from the tens of thousands of Scouts gathered at the 2005 jamboree. The speech came at a time of growing national tension over the wars in Iraq and Afghanistan, and Bush's popularity was nearing what was then a low point, largely as a result of his handling of the conflicts. Without discussing politics specifically, he struck a somewhat defiant tone, invoking War on Terror rhetoric in his speech.

“Lives of purpose are constructed on the conviction there is right and there is wrong, and we can know the difference,” Bush said, a group of Scouts in matching beige uniforms standing behind him. “You'll find that confronting injustice and evil requires a vision of goodness and truth.”

“All of you are showing your gratitude for the blessings of freedom,” he continued. “You also understand that freedom must be defended, and I appreciate the Scouts' long tradition of supporting the men and women of the United States military. Your generation is growing up in an historic time, a time when freedom is on the march, and America is proud to lead the armies of liberation.”

Follow your conscience, Bush told the Scouts, and serve a cause greater than yourself.

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President Barack Obama (2010)

Obama didn't attend the jamboree at Fort A.P. Hill in Virginia in 2010, which marked the 100th anniversary of the Boy Scouts of America. But he did send the Scouts a brief videotaped message praising the organization's history of community service and legacy of producing national leaders (he noted that 11 of the 12 people who walked on the moon were Scouts).

“That service is worth celebrating, but there's still more to do,” Obama said. “In the years ahead we're going to depend on you, the next generation of leaders, to move America forward.”