Tom Wheeler is leaving his job as the chairman of the Federal Communications Commission to make way for a new Republican administration. (David Ramos/Getty Images)

On any other day, Tom Wheeler would have folded his towering, 6-foot-4 frame into a tiny blue Mini Cooper and driven the four miles to his job as chairman of the Federal Communications Commission, where he was embroiled in a historic controversy over whether to slap new regulations on America’s Internet providers.

On one side were some of the country’s biggest corporations, arguing there was no need for new rules. On the other were consumer advocates who claimed the largest providers sought new business models that could ultimately harm ordinary Americans.

But on this cool November morning in 2014, Wheeler found himself face-to-face with a handful of those advocates in his driveway. Blocking his commute, the demonstrators unfurled a banner that read “Save the Internet!”

The confrontation, which was later uploaded to YouTube, clearly caught Wheeler off-guard. At first he tried to play along, standing behind the banner in a suit and tie while grinning for the cameras. But the protesters made clear they were not there for a photo op.

“Which side are you on, Tom?” they sang. “Are you with the people, Tom, or with the telecoms?”

After asking the protesters to leave, Wheeler retreated inside his Georgetown home. A few minutes later, the former top lobbyist for the cable and wireless industries stepped outside again and walked roughly a mile to the nearest subway station, where he caught a train to his office in Southwest Washington.

Over three years leading the FCC, Wheeler, a Democrat, has applied the same drive to addressing the nation's thorniest technology issues. Once pilloried by consumer advocates and the comedian John Oliver as a shill for big business, Wheeler took many by surprise as he brought challenge after challenge to the dominance of the companies he once represented.

“I have always been the insurgent versus the incumbent,” Wheeler, 70, said in an interview with The Washington Post on Tuesday, three days before leaving his post to make way for a Republican administration.

Accusing the broadband industry of stifling competition with misleading marketing and unscrupulous business practices, Wheeler pushed through an unprecedented set of rules to ban the blocking or slowing of websites. He forced Internet providers to submit to sweeping new privacy regulations aimed at preventing them from abusing customer data. And he moved to block the merger of Comcast and Time Warner Cable, a deal that, in the government's view, would have created a communications titan threatening rivals such as Netflix and YouTube.

Welcoming the votes of his Republican colleagues when it was politically convenient, forging ahead unilaterally when it wasn't, Wheeler sought to turn a staid federal office better known for policing celebrity wardrobe malfunctions and distributing airwave licenses into a consumer protection agency that would shape U.S. companies and technologies of the future.

But now a dark cloud looms over Wheeler's legacy as Republicans — led by President-elect Donald Trump — prepare to undo some of the most significant regulations approved under his watch.

No policy inspires as much fury among technologically minded Republicans as net neutrality, a signature FCC initiative that turned Internet service into a kind of 21st-century utility. Subjecting Internet providers to the same obligations that traditional phone companies must meet, Wheeler's decision to ram the policy through over conservative objections led to intense outrage from his political opponents. A federal court upheld the rules last summer in the face of an industry lawsuit, appearing to settle the matter once and for all.

“If it perseveres, it will go down in history as one of the biggest decisions the commission ever made,” said Michael Copps, who served as an FCC commissioner from 2001 to 2011 and as acting chairman for a stint in 2009, in an interview with The Post.

But Wheeler might not be so lucky. Opponents of the policy have argued that it unfairly tips the scale of business in favor of tech companies and goes beyond the authority vested in the agency. Several of these critics are on Trump's transition team, leading analysts to conclude a rollback of net neutrality is all but inevitable.

“Net neutrality has a big target on its back,” said Robert Kaminski, a telecom analyst at Capital Alpha Partners.

“If perchance [net neutrality] would be sidelined or eliminated,” said Copps, who is now a special adviser to Common Cause, which promotes open government, “then it'll just be kind of a footnote in history.”

That same fate may be in store for Wheeler's broader regulatory philosophy. As America's commerce and communications shift increasingly to the Internet, Wheeler has argued, regulators must ensure the principles that once protected consumers on older platforms — such as the nation's aging landline telephone network — are not abandoned.

Wheeler’s tenure was marked by numerous attempts to bring older regulations in line with a more technologically sophisticated age. He pushed to expand a subsidy program for low-income cellphone users, letting them apply a $9.25-a-month benefit toward buying mobile data and acknowledging that Americans are increasingly dependent on smartphones to find jobs and seek information. Schools and libraries gained greater access to federal funds set aside for broadband subscriptions. And he sought to make life easier for Americans with disabilities.

Sensing the threat to his most ambitious policies, Wheeler warns that anyone seeking to dismantle his agency's work could face a backlash from consumers.

“The effort that is now underway, much talked about, to repeal the open Internet, is something that will benefit six companies,” said Wheeler in Tuesday’s interview, referring to the handful of providers who, for many Americans, represent their only on-ramp to the Web. “And tens of thousands of companies and millions of consumers will be affected.”

“Competition, competition, competition” has been a mantra of Wheeler's tenure. While in office, he sought to break up what he called a “duopoly” in many markets for high-speed Internet, at times boldly inviting legal scrutiny. Last year, he and the FCC's two other Democrats moved to block state limits affecting mayors who wanted to build out their own, publicly operated challengers to companies such as Comcast and Verizon.

Wheeler's decision to intervene on behalf of Wilson, N.C., and Chattanooga, Tenn., over how widely they could offer service led to a lawsuit from industry defenders accusing the FCC of unconstitutionally meddling in state-level affairs. Wheeler's lawyers responded that it was the FCC's duty, by congressional charter, to promote the spread of broadband, and that the agency had the authority to eliminate impediments to that mission. At the time, analysts described it as a creative legal theory. But it failed in court, in a rebuke to the FCC's expansive view of its own role in shaping the broadband market.

Wheeler's activist approach may now be counteracted by the forces of deregulation under Trump.

Critics of the FCC have accused Wheeler of looking too much to the past as a guide to the future. The sometime historian — Wheeler has written two books on President Abraham Lincoln and the Civil War — is fond of comparing today's Internet networks with their 19th-century counterparts, the railroad and the telegraph. But the 21st century, according to opponents, operates differently.

“I think Tom has been very vocal in wanting to restore the historical predicates,” said Michael Powell, who leads the Internet and Television Association, a top cable-industry trade group, in a September interview. Powell, a Republican, headed the FCC under President George W. Bush and was one of Wheeler's top adversaries during the Obama years.

But, Powell added, “they're basically really ancient, old, sometimes discredited notions of how to organize regulatory thinking.”

Powell and his allies successfully fought Wheeler to a standstill on a number of issues, particularly in the run-up to the election. One, a proposal to force companies to provide better and cheaper cable set-top boxes, could have allowed new entrants such as Google or Amazon to build competing TV devices. Opposed by cable providers and stymied by a political chasm dividing Wheeler's own party, the rules were pulled off the agenda last fall and never made it back on.

Wheeler, who will spend at least the next three months at the Aspen Institute as a senior fellow, regrets not having more time to push the deal through. But, he said, companies that seek to shut other businesses out in a bid to maintain dominance are on the wrong side of history.

“History has always had it that American networks are open networks,” he said. “And that if the effort becomes to favor a half-dozen companies at the expense of tens of thousands of other companies that rely on the open Internet, and millions of consumers that rely on an open Internet, I don't think that will be the end.”