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

WASHINGTON ― In early 2014, as his domestic agenda languished with a Republican Congress, President Barack Obama undertook what White House staffers called the “pen-and-phone” strategy. Unable to overcome GOP opposition on Capitol Hill, the president vowed to implement whatever reforms he could through executive action. “We’re not just going to be waiting for legislation in order to make sure that we’re providing Americans the kind of help they need,” he told his Cabinet members. “I’ve got a pen, and I’ve got a phone.”

In the months that followed, he unleashed a slew of new rules and executive actions meant to improve job conditions and boost paychecks. He signed an order raising the minimum wage for workers under federal contracts to $10.10 per hour. He signed another guaranteeing them paid sick days. He went after financial advisers who reap large fees from retirement plans. And most significantly, he reformed the country’s overtime rules to make them more generous to workers, potentially making millions of salaried employees eligible for time-and-a-half pay when they work more than 40 hours in a week.

Now, in the last days of his presidency, those reforms exemplify Obama’s successes and shortcomings as he wrestled with Republicans over his economic agenda for six years. The White House genuinely believed those kinds of changes would improve the lives of poor and middle-class workers. They pursued them in the face of heavy lobbying from powerful business groups. And in carrying them out, they expected to burnish Obama’s legacy as a president who helped shape a fairer economy for the folks at the bottom, with or without cooperation from Congress.

Those particular reforms might not survive even the first year of Donald Trump’s presidency. Just as Obama promised to use his pen and phone, so has the incoming president. Trump can wield his own to vacate much of what his predecessor did, underscoring the fragility of many of the outgoing president’s accomplishments. Try as he did to change the rules of the workplace, the economic system Obama inherited will end up largely intact as he exits.

“I think Obama will go down in history as a great president. He did a lot of great things,” said Dan Schlademan, a longtime labor organizer who helped found the worker group OUR Walmart. “But transformational presidents shift power. He didn’t shift power. The people who had power in 2008 still have it. And those who didn’t still don’t.”

Before Obama could even think about shifting structural power, he had to stop the country from hemorrhaging jobs. The Great Recession and its aftermath consumed his first term, and his priority was to keep as many people employed as possible. History will judge him well on this front, said Lawrence Mishel, an economist and president of the Economic Policy Institute, a liberal research group. With help from Congress, Obama extended unemployment benefits for laid-off workers. He pumped vast stimulus into the economy, both through infrastructure spending and aid to states. And he extended a crucial rescue of the auto industry that began under President George W. Bush.

“That was over the resistance of his economic team,” Mishel said of the auto bailout. “It was brave, and it was politically unpopular, except in the Upper Midwest. That had a huge effect.”

By mitigating unemployment early in his tenure, Obama’s actions helped maintain workers’ bargaining power in the short term. But he missed what was widely seen on the left as a chance to boost bargaining power in the long term, and perhaps permanently, through the Employee Free Choice Act. A holy grail for organized labor, the bill would have changed labor law to make it easier for workers to join unions, creating a potentially transformative power shift. It could have helped stem the decline of organized labor, which now represents less than 7 percent of private-sector workers.

Through executive action, he walked the walk. Lee Saunders, president of the American Federation of State, County and Municipal Employees

Democrats had their chance when they held both chambers of Congress and Obama occupied the White House. The president poured his efforts into what would turn out to be his signature legislative achievement, the Affordable Care Act. “He did ask that we put our efforts behind the health care fight and get it done,” recalled Bill Samuel, director of government affairs for the AFL-CIO labor federation. “With the momentum, he felt he would be with us in getting EFCA through Congress…. That would be a big change, maybe transformational.” Of course, Democrats ended up losing the House in 2010 and the Senate in 2014, making EFCA a non-starter for the rest of his presidency.

Facing a GOP-controlled Congress for most of his tenure made progressive economic legislation all but impossible for Obama. Nothing demonstrates the pushback he faced quite like the fight over the minimum wage. The federal wage floor is $7.25 per hour, and it hasn’t been raised since 2009, after the last of a series of increases George W. Bush signed into law. Obama will leave office later this month with an awkward distinction: Barring a legislative miracle, he will be the first president of either party since Ronald Reagan to not sign a minimum wage package.

That’s not for a lack of trying. Ever since his 2013 State of the Union speech, Obama has pressured Republicans for a minimum wage increase. And while Washington has stalled, cities and states around the country have continued to raise their minimum wages with broad approval from the electorate.

Jim Manley, a Democratic lobbyist who worked on increases as a congressional staffer during the Bush and Clinton years, said the issue symbolizes the climate Obama faced on Capitol Hill. Opposing minimum wage hikes has become “a part of the Republican ideology,” Manley said. “In years past, there were moderate Republicans that would support a moderate increase. That’s just not the case these days. And we fall further and further behind.”

The gridlock in Congress left Obama with reforms that were inherently limited but significant nonetheless. He and his Labor secretary, Tom Perez, used the federal government’s contracting power to raise standards in the workplace, taking up the mantle of Franklin D. Roosevelt and other liberal presidents. In addition to ensuring contract workers higher wages and paid leave, the Obama administration also proposed barring employers with a history of wage theft and documented workplace hazards from getting federal money. They also put new wage and safety regulations on the books to protect coal miners, construction workers and home care workers, reforms that had been decades in the making. And the appointments Obama made to the National Labor Relations Board have made it easier for many workers to organize.

All those reforms are evidence Obama did what he could under the circumstances, argued Lee Saunders, president of the American Federation of State, County and Municipal Employees. “He can always do more, but if you look at his record, he was really supportive of working families,” said Saunders. “Through executive action, he walked the walk.”

I think Obama will go down in history as a great president. ... But transformational presidents shift power. He didn't shift power. Dan Schlademan, co-founder of OUR Walmart

But while Obama is considered one of the great orators of his office, he failed to convey the totality of his plan for improving jobs. Mishel said that the president had a bold and comprehensive agenda on wages ― but that wasn’t clear even to many of the workers who would benefit from it. “The administration was taking a lot of aggressive action,” Mishel said. “One disappointment to me [is] they didn’t really communicate that to the American people.”

Obama was often selective in his use of the bully pulpit. While he would frequently proselytize for a higher minimum wage, the president didn’t talk often about the virtues of collective bargaining, at least not until late in his tenure. That sometimes frustrated labor leaders who knew the president supported their cause but usually reserved his union talk for union crowds, even at a time when organized labor was fighting battles around the country.

“He was formidable, and history will view him very positively given the hand he was dealt. I think that today’s numbers make that clear,” said Randi Weingarten, president of the American Federation of Teachers union. “But he never conveyed to people effectively enough that he understood everybody’s pain…. People don’t feel better. They don’t see it and they don’t hear it.”

Trump’s election has surely endangered much of Obama’s work, but some of his reforms in the U.S. workplace will live on regardless. For instance, even if Obama’s overtime rule is blocked in court or killed by the Trump administration, it will still have boosted wages for a number of salaried workers. A lot of companies have already given their workers raises in order to exempt them from overtime eligibility, which is exactly what the Obama administration hoped would happen. That includes Walmart, which raised its base salary several thousand dollars in anticipation of the legal changes.

Perhaps, in the end, thousands of people benefit from the reform rather than the millions the White House had envisioned. Whoever they are, they’ll have Obama to thank for it.