Jean Edward Smith is professor emeritus at the University of Toronto and the author of "BUSH," a biography of the 43rd president.

Former president George W. Bush speaks during the Presidential Leadership Scholars graduation on July 14 at Little Rock Central High School in Little Rock. (Gareth Patterson/AP)

George W. Bush left office in January 2009 with an approval rating that hovered in the 20s — the lowest of any president in modern times. Today, that rating is in the high 40s and low 50s. That is not because the public has changed its mind about the war in Iraq or the domestic excesses of his administration. To the contrary, public opinion is even more negative.

The reason for the recovery of Bush’s approval rating is his post-presidential behavior. As an ex-president, Bush has been exemplary. He has avoided the limelight and stayed out of the political arena. He has not criticized President Obama and, except for very briefly supporting his brother Jeb’s quest for the GOP nomination in Florida, has steered clear of presidential politics.

That is exactly what an ex-president should do. While in office, a president dominates the nation’s political discourse. But after leaving the White House, that time is over, and he or she should move to the sidelines.

Dwight Eisenhower and Ronald Reagan did that remarkably well, and so has George W. Bush. One of Bush’s spokesmen said recently that Bush will not vote for either Hillary Clinton or Donald Trump in November, but the former president has said nothing. Bush obviously recognizes the difficulty of being president and does not wish to be drawn back into the fight. “When I saw his hand go up, I thought, ‘Free at last,’ ” he told friends in Dallas after Obama’s inauguration.

Bush came into office in 2001 believing he was God’s agent here on Earth to rid the world of evil. And that largely explains the excesses of his administration. By 2008, he had become much more aware of the limitations of the office and his own shortcomings. When the financial downturn occurred that year, he listened to Secretary of the Treasury Hank Paulson and Chairman of the Federal Reserve Ben Bernanke and took the action necessary to avoid another Great Depression — action contrary to his deepest beliefs.

When Obama defeated John McCain in the election, Bush took every step possible to ease the transition, and openly welcomed Barack and Michelle to the White House. When he returned to Texas, he rejoiced at being out of Washington. “The presidency was a joyful experience,” he told a crowd in Midland when he returned, “but nothing compares with Texas at sunset. It is good to be home.”

In Dallas, Bush took up the duties of a private citizen. He and Laura purchased a large house in the Preston Hollow section of North Dallas and alternating between living there and the ranch in Crawford. Bush did not participate in the congressional elections of 2010 and 2014 or in Mitt Romney’s bid for the presidency in 2012. He addressed the GOP convention that year, but by video hookup and not in person. With the exception of immigration reform — which he continues to advocate — he has avoided taking stands on public issues and devoted himself to private endeavors, particularly the fight against AIDS in Africa.

Bush wrote his memoirs, which were published in 2010, and then a book about his father, which was published in 2014. Both were well received. Like Clinton, he began to speak privately to elite audiences, charging fees of between $100,000 and $150,000 for each appearance. He also took up golf and became a regular at Dallas golf courses. “It requires discipline, patience, and focus … a couple of areas where I could use some improvement,” he quipped.

Like Eisenhower and Winston Churchill, he also took up painting. As Laura said, “He was desperate for a pastime.” In April 2014, he exhibited two dozen portraits of world leaders he had known. “Painting has changed my life in an unbelievably positive way,” he told a reporter for ABC News. Eisenhower and Churchill could have said the same.

Unlike Bill Clinton and Jimmy Carter, Bush does not miss the presidency. “I really don’t,” he told an audience in Houston in 2011. “I actually found my freedom by leaving Washington.”

Former President George W. Bush spoke at a memorial service for five Dallas police officers killed on July 7, saying "we do not want the unity of grief, nor do we want the unity of fear." (Reuters)

Last week, Bush and Laura appeared with the Obamas at the ceremony in Dallas honoring the five police officers who had been killed. His remarks were eloquent. “Too often, we judge other groups by their worst examples, while judging ourselves by our best intentions. And this has strained our bonds of understanding and common purpose. … We have never been held together by blood or background. We are bound by things of the spirit, by shared commitments to common ideals. … This is the bridge across our nation’s deepest divisions. And it is not merely a matter of tolerance, but of learning from the struggles and stories of our fellow citizens and finding our better selves in the process.”

George W. Bush’s decision to invade Iraq in 2003 was the worst foreign-policy decision ever made by an American president. Saddam Hussein was not involved in 9/11, there was no al-Qaeda presence in Iraq and no weapons of mass destruction. Iraq was the most secular state in the Middle East, and there was no Islamic State — the terrorist threat we face today. But that does not mean Bush was America’s worst president. His domestic achievements were significant, including No Child Left Behind and prescription drugs for seniors. Even more important, his decisive actions in 2008 avoided another Great Depression. And he has emerged during his post-presidential years as a person who deserves our continuing respect.