WASHINGTON – While President Barack Obama “will be running through the tape on Jan. 20, working on issues,” as Ben Rhodes, his deputy national security advisor, vividly put it on Friday, President-elect Donald Trump is planning how to reverse key pieces of Obama’s legacy starting on the first day of his presidency.

Trump will be able to eliminate a host of Obama’s achievements, some with the stroke of a pen.

“A significant portion of the Obama legacy is vulnerable on Day One because, feeling himself checkmated by Congress, President Obama resorted to executive orders with increasing frequency as his presidency went on,” said William Galston, a senior fellow at the center-left Brookings Institution who served in the Bill Clinton White House.

Obama, whose upbeat campaign of hope and change won him the White House in 2008, was confronted with a divided government after Republicans grabbed control of the Senate following the 2014 mid-term elections, having wrested the House from Democrats in 2010.

With Republicans holding Congress – erecting a GOP blockade that remains to this day – Obama devised an end run strategy. As he put it in a Cabinet meeting on Jan. 14, 2014: “I’ve got a pen and I’ve got a phone — and I can use that pen to sign executive orders and take executive actions and administrative actions that move the ball forward.”

If Hillary Clinton had won Tuesday’s election, Obama would have passed the baton in a seamless transition where none of his orders or actions would have been revoked. After one of the darkest and most ugly campaigns in memory, Trump’s scorched campaign rhetoric suggested a hostile takeover.

Trump on Friday was pulling back from his major campaign pledge to “repeal and replace” the Affordable Care Act, the health insurance plan that is at the top of Obama’s major domestic legacy. Trump’s switch came after meeting with Obama in the Oval Office on Thursday.

Calling Obamacare a “disaster” on the campaign trail, Trump told the Wall Street Journal and CBS’ “60 Minutes” that he wants to keep two popular provisions: letting youths up to the age of 26 remain on their parents policies and forbidding insurers to ban people with pre-existing conditions.

Insurers are not likely to resist keeping healthy younger people on a family policy. Obamacare requires everyone to buy health insurance – or pay a penalty – because if only sick people buy insurance, costs increase. Trump told the Wall Street Journal that Obamacare will be “amended, repealed or replaced.”

Trump now faces the challenge of how to work with Republicans in Congress to convince health insurance companies to keep pre-existing condition coverage while dropping the unpopular policy purchase mandate and at the same time cut premiums. Obama and Democrats have said they would be open to amendments that could improve Obamacare while maintaining the guarantee of health insurance coverage.

In the meantime, the Obama administration after the election cranked up its drive to get people to sign up for coverage starting in 2017 — and more than 100,000 consumers signed up on Wednesday, the day after Trump was elected.

On other Obama big legacy items:

  • TPP: Trump’s election means a potential major Obama legacy, winning congressional approval of the Trans-Pacific Partnership trade deal, is dead.
  • Illegal immigrants: Trump can revoke the Deferred Action for Childhood Arrivals (DACA) executive order Obama issued in 2012, allowing youths, known as “Dreamers,” in the U.S. illegally through no fault of their own to stay. The same for the Deferred Action for Parents of Americans and Lawful Permanent Residents – DAPA- which covers the parents of the youths. An issue is whether Trump would make deportation of this now protected class a priority.
  • Iran nuclear deal: This would be tricky for Trump to kill or renegotiate since the U.S. is just one of the parties to the deal.
  • Climate: Trump believes global warming is a “hoax.” He wants to pull the U.S. out of the 2016 landmark Paris Climate agreement. Trump can just do nothing about living up to the U.S. pledges to reduce greenhouse gas emissions.
  • Supreme Court: Obama’s potential legacy of naming a third justice – Lincolnwood native Merrick Garland – now will not happen.
  • LGBTQ advances: Trump has pledged to revoke a 2014 Obama executive order banning federal contractors from discriminating on the basis of sexual orientation or gender identity.

Obama has been using his clemency power through the years to reduce long sentences for non-violent drug offenders. Trump cannot reverse Obama’s commutations. More are expected before he leaves office

“The President has made this a priority,” White House Press Secretary Josh Earnest said on Thursday. “…So I do think that’s an important part of his legacy.”