Shirley Anne Warshaw, director of the Fielding Center for Presidential Leadership Study at Gettysburg College, said Mr. Trump is not unusual in making a clean break from his predecessor. “Trump isn’t doing anything that Obama didn’t do,” she said. “He is simply reversing policies that were largely put in place by a president of a different party.”
The difference, she said, is that other presidents have proactive ideas about what to erect in place of their predecessor’s programs. “I have not seen any constructive bills in this vein that Trump has put forth,” she said. “As far as I can tell, he has no independent legislative agenda other than tearing down. Perhaps tax reform.”
With flourish, Mr. Trump has staged signing ceremonies meant to show him tearing down. Not only did he pull out of the Trans-Pacific Partnership trade deal and the Paris climate accord, he approved the Keystone XL pipeline Mr. Obama had rejected and began reversing his fuel-efficiency standards and power plant emissions limits. Not only is he trying to repeal Obamacare, he has pledged to revoke regulations on Wall Street adopted after the financial crash of 2008.
Still, he has not gone as far as threatened. He has for now kept Mr. Obama’s nuclear agreement with Iran, however reluctantly, and while he made a show of overturning Mr. Obama on Cuba, the fine print left much of the policy intact. He did not rescind Mr. Obama’s order sparing younger illegal immigrants from deportation. Senate Republicans released a new version of legislation to repeal and replace Obamacare in recent days, but it may yet end in impasse, leaving the program in place.
Advisers insist Mr. Trump is not driven by a desire to unravel the Obama presidency. But like the Manhattan real estate developer he is, they said, he believes he must in some cases demolish the old to make way for the new.
“He hasn’t dismantled everything, and I don’t know that that’s exactly what he’s looking to do,” said Hope Hicks, the White House director of strategic communications. “That may be a side effect of what he’s building for his own legacy. I don’t think anybody’s coming into the office every day saying, ‘How can we undo Obama’s legacy, and how can he go back?’ ”
Yet Mr. Trump has depicted the Obama legacy as a disastrous one that needs unraveling. “To be honest, I inherited a mess,” he said at a news conference soon after taking office. “It’s a mess. At home and abroad, a mess. Jobs are pouring out of the country. You see what’s going on with all of the companies leaving our country, going to Mexico and other places, low pay, low wages, mass instability overseas no matter where you look. The Middle East is a disaster. North Korea. We’ll take care of it, folks.”
Critics say Mr. Obama brought this on himself. His biggest legislative achievements were passed almost exclusively with Democratic votes, meaning there was no bipartisan consensus that would outlast his presidency. And when Republicans captured Congress, he turned to a strategy he called the pen and the phone, signing executive orders that could be easily erased by the next president.
“I’ve heard it joked about that the Obama library is being revised to focus less on his legislative achievements as each week of the Trump administration goes by,” said Matt Schlapp, chairman of the American Conservative Union. “It’s like living by the sword and dying by the sword. When your presidency is based on a pen and a phone, all of that can be undone, and I think we’re seeing that happening rather systematically.”
Mr. Obama would argue he had little choice because of Republican obstructionism. Either way, he has largely remained quiet through the current demolition project, reasoning that speaking out would only give Mr. Trump the public enemy he seems to crave. He made an exception on Thursday, taking to Facebook to assail the new Senate health care bill as “a massive transfer of wealth from middle class and poor families to the richest people in America.” But Mr. Obama’s team takes solace in the belief that Mr. Trump is his own worst enemy, better at bluster than actually following through.
“Obama’s legacy would be under much greater threat by a more competent president than Donald Trump,” said Josh Earnest, who served as Mr. Obama’s White House press secretary. “His inexperience and lack of discipline are an impediment to his success in implementing policies that would reverse what Obama instituted.”
Other Obama veterans said much of what Mr. Trump has done was either less dramatic than it appeared or reversible. He did not actually break relations with Cuba, for instance. It will take years to actually withdraw from the Paris accord, and the next president could rejoin. The real impact, they argued, was to America’s international reputation.
“There’s a lot of posturing and, in fact, not a huge amount of change, and to the extent there has been change, it’s been of the self-defeating variety,” said Susan E. Rice, the former national security adviser. “What’s been happening is not that the administration is undoing President Obama’s legacy, it’s undoing American leadership on the international stage.”
Mr. Trump, of course, is hardly the first president to scorn his predecessor’s tenure. George W. Bush was so intent on doing the opposite of whatever Bill Clinton had done that his approach was called “ABC” — Anything but Clinton. Mr. Obama spent years blaming his predecessor for economic and national security setbacks — blame that supporters considered justified and that Mr. Bush’s team considered old-fashioned buck passing.
For decades, presidents moving into the Oval Office have made a point on their first day or two of signing orders overturning policies of the last tenant, what Mr. Riley called “partisan kabuki” to signal that “a new president is in town.”
The most tangible example is an order signed by Ronald Reagan barring taxpayer financing for international family planning organizations that provide abortion counseling. Mr. Clinton rescinded it when he came into office. Mr. Bush restored it, Mr. Obama overturned it again and Mr. Trump restored it again.
Even so, neither Mr. Bush nor Mr. Obama invested much effort in deconstructing programs left behind. Mr. Bush kept Mr. Clinton’s health care program for lower-income children, his revamped welfare system and his AmeriCorps service organization. Mr. Obama undid much of Mr. Bush’s No Child Left Behind education program, but kept his Medicare prescription medicine program, his AIDS-fighting program and most of his counterterrorism apparatus.
That was in keeping with a longer tradition. Dwight D. Eisenhower did not unravel Franklin D. Roosevelt’s New Deal, nor did Richard M. Nixon dismantle Lyndon B. Johnson’s Great Society. Mr. Reagan promised to eliminate the departments of Education and Energy, created by Jimmy Carter, but ultimately did not.
Mr. Obama understood that his legacy might be jeopardized by Mr. Trump. During last year’s campaign, he warned supporters that “all the progress we’ve made over these last eight years goes out the window” if Mr. Trump won. Only after the election did he assert the opposite. “Maybe 15 percent of that gets rolled back, 20 percent,” he told The New Yorker’s David Remnick. “But there’s still a lot of stuff that sticks.”
Indeed, when it comes time to tally the record for the history books, Mr. Trump can hardly reverse some of Mr. Obama’s most important achievements, like pulling the economy back from the abyss of a deep recession, rescuing the auto industry and authorizing the commando raid that killed Osama bin Laden. Nor can Mr. Trump take away what will surely be the first line in Mr. Obama’s obituary, his barrier-shattering election as the first African-American president.
Conversely, Mr. Obama owns his failures regardless of Mr. Trump’s actions. History’s judgment of his handling of the civil war in Syria or the messy aftermath of the intervention in Libya or the economic inequality he left behind will not depend on his successor. If anything, America’s decision to replace Mr. Obama with someone as radically different as Mr. Trump may be taken as evidence of Mr. Obama’s inability to build sustained public support for his agenda or to mitigate the polarization of the country.
But legacies are funny things. Presidents are sometimes defined because their successors are so different. Mr. Obama today is more popular than he was during most of his presidency, likely a result of the contrast with Mr. Trump, who is the most unpopular president this early in his tenure in the history of polling. By this argument, even if Mr. Trump does disassemble the Obama legacy, it may redound to his predecessor’s historical benefit.
Richard Norton Smith, who has directed the libraries of four Republican presidents, said presidents are often credited with paving the way toward goals that may elude them during their tenure. Harry S. Truman is called the father of Medicare even though it was not achieved until Johnson’s presidency. Mr. Bush is remembered for pushing for immigration reform even though Congress rebuffed him.
“It’s hard to imagine future historians condemning Barack Obama for breaking with his country’s past ostracism of Cuba or joining the civilized world in combating climate change or pursuing a more humane and accessible approach to health care,” Mr. Smith said. “Indeed, we build memorials to presidents who prod us toward fulfilling the egalitarian vision of Jefferson’s declaration.”
But that may not be all that comforting to Mr. Obama. Presidents prefer memorials to their lasting accomplishments, not their most fleeting.