All the living presidents came together here Thursday to pay tribute to one of their own, and for one brief moment, George W. Bush’s presidency was free of controversy.

In office, the nation’s 43rd president lived through eight tumultuous years. But as he and dignitaries from around the world joined to dedicate the George W. Bush Presidential Library and Museum on the campus of Southern Methodist University, there was no mention of Iraq, no talk of Hurricane Katrina, no reference to the financial collapse that marked his last months in office.

The dedication of the library may have reopened the debate over Bush’s presidency, giving historians, commentators and partisans an opportunity to appraise and reappraise his tenure. But that wasn’t the mission of the members of the most exclusive club in the world, as the group of current and former presidents is called. One after another, they found ways to accentuate the positive.

His fellow presidents described Bush as strong, resolute, courageous and compassionate. He drew praise for defending the country after the Sept. 11, 2001, terrorist attacks and for saving lives in Africa with his initiative to combat HIV/AIDS. He was commended for trying to reform the country’s immigration system, an issue that is back on the national agenda.

Jimmy Carter made a passing reference to the disputed 2000 election, but the closest anyone really got to the controversies of his presidency was Bush himself. Noting that one hallmark of free people is the right to disagree with each other and with their leaders, the former president said, “I created plenty of opportunities to exercise that right.”

An emotional President George W. Bush called his presidency “an honor of a lifetime” at the dedication of his presidential library Thursday in Dallas, Texas. (JulieAnn McKellogg/The Washington Post)

President Obama led the tributes, joined by former presidents Bill Clinton, Carter and Bush’s father, George H.W. Bush. The elder Bush was in a wheelchair and gave only brief remarks. But he was hearty enough to stand, haltingly and with help from his wife, Barbara, and his son, to acknowledge a standing ovation from thousands of people gathered on a sun-splashed plaza outside the entrance to the library and museum.

Obama noted that the last time the living presidents all met was just before he took office in 2009. “I needed that,” he said. “Because as each of these leaders will tell you, no matter how much you may think you’re ready to assume the office of the presidency, it’s impossible to truly understand the nature of the job until it’s yours, until you’re sitting at that desk.”

It is why, when decades of Oval Office experience are on the same stage, that the presidents all strive for mutual respect, even if their personal relationships are at best proper or even occasionally frosty, as is the case between Bush and the president who succeeded him.

Obama has criticized Bush for invading Iraq, for taking his eye off the ball in Afghanistan and for policies that he said led to the financial collapse in 2008. But on Thursday, he found plenty to like in his predecessor. He called Bush “a good man” who is “comfortable in his skin.” Beyond the personal, he said that when the country was attacked on Sept. 11, Bush responded laudably.

“As we walk through this library, obviously we’re reminded of the incredible strength and resolve that came through that bullhorn as he stood amid the rubble and the ruins of Ground Zero, promising to deliver justice to those who had sought to destroy our way of life,” Obama said.

Bush displayed the full range of emotions. He laughed as he listened to others speak and as he traded asides with his father. “Oh, happy day,” he said when he took the microphone. He was self-deprecating. “There was a time in my life when I wouldn’t be found at a library, let alone found one,” he said.

But he turned serious when he spoke of the events that transformed his presidency and of what he said was the guiding principle of that presidency, which was the advancement of freedom around the world.

“When our freedom came under attack, we made the tough decisions required to keep people safe,” Bush said. Whether people agree or disagree with choices he made, he said, visitors to his museum would find “we stayed true to those principles.”

As he finished, his voice was choked with emotion. He wiped away a tear when he sat down.

Clinton joked that he has developed such a close relationship with the elder Bush and shares stages so often with the younger Bush that he has become “the black-sheep son” of the family. “My mother told me not to speak too long, and Barbara, I will not let you down,” he said.

He was generous in praising Bush for the initiative to combat HIV/AIDS in Africa, saying no president in his party could have gotten such legislation through Congress. He said he has seen the faces of people whose lives were saved by Bush’s efforts.

Carter echoed that theme in his brief remarks, thanking Bush for helping the neediest people on Earth.

What wasn’t said by any of the speakers, but what the assemblage of presidents symbolized, was the degree to which George W. Bush’s presidency ushered in two eras.

One, obviously, was America in the age of terrorism. Terrorist attacks took place in other presidencies and al-Qaeda struck repeatedly during Clinton’s presidency. But 9/11 and Bush’s response changed the way the country thought about and responded to these threats.

The second was the realization that red-blue divisions and partisan polarization became a permanent part of the country’s politics during Bush’s presidency. The country was moving in that direction even before he was sworn in, notably with the Republican takeover of Congress in 1994. But Bush’s presidency solidified those differences, which have become even more deeply etched in the years since.

As the current and former presidents and their spouses sat onstage together, it was impossible not to recall the degree to which the Bush and Clinton families have defined the politics of the past three decades, or to think about what impact they could have on the future.

The recession that hit during the elder Bush’s presidency made Clinton’s presidency possible. George W. Bush redeemed his father’s loss in a race against Clinton’s vice president. Obama’s presidency was made possible in part by revulsion against Bush’s presidency and the Iraq war — which Hillary Rodham Clinton, who just stepped down as Obama’s secretary of state, voted to authorize as a senator.

Now Hillary Clinton is the early favorite of Democrats to lead their party in 2016. Former Florida governor Jeb Bush, the 43rd president’s brother, is looking at running for the Republican nomination. Bill Clinton is encouraging his wife to run. George W. Bush has said he hopes his brother will do so. But Barbara Bush told NBC’s Matt Lauer on Thursday that she hopes Jeb doesn’t run. “We’ve had enough Bushes,” she said.

Jeb Bush and the voters will decide that, but there is little doubt that if he were to run, his brother’s legacy would affect his chances, just as Obama’s and Bill Clinton’s would affect Hillary Clinton. So while Thursday was mostly about looking back, it also was a reminder that past can be prologue.