This piece is part of a series on Obama’s legacy that The Huffington Post will be publishing over the next week.

WASHINGTON ― Scandal has consumed the final four years of every two-term president in modern history ― George W. Bush, Bill Clinton, Ronald Reagan, Richard Nixon. Barack Obama’s administration is the exception.

While there were some minor scandals and resignations during Obama’s eight years in office, wrongdoing never fully occupied his presidency. None of it even directly touched the White House. There were no grand juries investigating his aides. There were no impeachments. There were neither convictions of White House staffers, nor pardons to protect government officials.

This was a significant departure from the previous four two-term presidents. George W. Bush’s second term featured convictions related to the Jack Abramoff lobbying scandal, in which more than a dozen lobbyists and government officials went to jail for corruption. There were also convictions related to the politically motivated purge of U.S. attorneys and the retaliatory leak of CIA agent Valerie Plame’s identity.

As everyone who was sentient in the 1990s recalls, Clinton was impeached over his affair with intern Monica Lewinsky. Reagan’s second term was plagued by corruption investigations ranging from Iran-Contra to Wedtech, a contracting scandal that led to the resignation of Attorney General Ed Meese. And, of course, there were Nixon’s final two years in office, which featured the convictions of 48 government officials and the first presidential resignation over corruption.

All of these past scandals directly involved White House staff.

Karl Rove, Bush’s top political adviser, and Lewis Libby, a senior adviser to Vice President Dick Cheney, both were implicated in leaking Plame’s name to the press in retaliation for an op-ed that her husband, former Ambassador Joe Wilson, wrote that showed that the president had lied about Iraq’s pursuit of nuclear weapons in his 2003 State of the Union address. While Rove was not prosecuted, Libby was convicted of obstruction of justice. Bush later commuted the sentence.

The Clinton administration’s major scandal was related to the president’s own actions.

The Iran-Contra scandal consumed the entire national security arm of the Reagan administration. At least eight members of the administration were indicted, and there were multiple convictions, although some were later overturned due to jury tampering, and President George H.W. Bush pardoned others.

The 1972 Watergate scandal and ensuing revelations of campaign finance violations, cover-ups and retaliations destroyed the Nixon administration.

It’s not an accident that Obama’s presidency was largely scandal-free. His former ethics adviser, Norm Eisen, began to craft an ethics plan for the administration months before the 2008 election. When Obama won, Eisen began implementing these plans with other White House aides ― including Chris Lu, who served as assistant to the president and later as deputy secretary of labor, and the late Cassandra Butts. Obama himself got engaged in the planning, reportedly making line-edits to the guidelines, according to Eisen.

Bloomberg via Getty Images President Barack Obama signs an executive order on ethics for his senior staff during a meeting in the Eisenhower Executive Office Building, adjacent to the White House, in Washington, D.C. on Jan. 21, 2009.

The plan required every Obama administration official and employee to sign an ethics pledge that included bans on accepting certain gifts and revolving-door rules that barred former staffers from lobbying the administration until Obama’s term ended. Officials leaving for other lines of work were banned from contacting their former agency for two years.

The administration also adopted a loose ban on registered lobbyists entering the administration. Not all of these commitments stuck. Obama granted waivers that allowed some lobbyists to be appointed to government positions. And lawyers who represented banks or other industries, but were not registered as official lobbyists, moved freely from the private sector to the public sector and back again.

By no means did the Obama administration thwart the power of special interests and big money in Washington. But the administration did avoid major scandals, which Eisen attributed to the “tone at the top.”

“Everyone knows the president himself is a man of great integrity,” Eisen said. “He cares about this, he talks about it.”

Still, there were examples of wrongdoing that led to resignations. Congress held Attorney General Eric Holder in contempt in the “Fast and Furious” investigation ― a botched Bureau of Alcohol, Tobacco and Firearms operation against gun smugglers from 2009 to 2011 that led to the death of a border control agent. Officials also resigned over the Internal Revenue Service’s alleged targeting of conservative groups for tax scrutiny, overspending on conferences at the General Services Administration, and hacking that exposed employee records at the Office of Personnel Management.

The years-long investigations into former Secretary of State Hillary Clinton’s response to the attack on a U.S. diplomatic mission in Benghazi revealed that she kept a private email server. While that did not lead to any charges or convictions, it may have contributed to her election defeat.

“Look I’m not saying everything the administration, the White House, has done is perfect,” Eisen said. But, he added, “You can’t compare those to the major scandals that have afflicted previous White Houses, where people have gone to jail. There’s been nothing like that under Obama.”

President-elect Donald Trump, meanwhile, is set to enter office with unprecedented conflicts of interest related to his business empire, already setting the tone for a very different administration. He appears to be doing very little to vet his cabinet appointees. Former House Speaker Newt Gingrich, the first speaker to be punished for ethics violations and a Trump ally, called for ethics laws to be loosened for Trump, and for the president-elect to issue preemptive pardons to appointees, so they won’t be punished for breaking the law.

While Trump was looking to fill out his Cabinet, he managed to consider the only major figure convicted of a crime in Obama’s eight-year administration. That person was former CIA Director David Petraeus.

CORRECTION: A previous version of this article mischaracterize d the U.S. mission in Benghazi as an embassy.