Passing the plan would be the biggest victory in Mr. Pai’s eventful 11-month tenure as the head of the F.C.C., helping secure his reputation as one of the most effective chairmen in decades. Under his leadership, the agency has already opened the door for more media mergers, curtailed a high-speed internet program for low-income families and allowed broadband providers to raise rates to business customers.
All of this activity has made Mr. Pai, 44, a former lawyer for Verizon and a longtime government bureaucrat, the target of many angry protests. In recent days, government officials — including 18 state attorneys generals and dozens of Democratic members of Congress — have asked the F.C.C. to delay the vote. On Wednesday, the attorneys general said that many of the 23 million public comments that had been filed to the agency about net neutrality appeared to be fraudulent. Mr. Pai has ignored the delay requests.
But Mr. Pai’s changes have also won him political accolades and distinction as a high achiever in the Trump administration’s rush to shed regulations. The effects of his decisions have rippled across the industries Mr. Pai oversees. The looser rules on media ownership, for example, has enabled Sinclair Broadcasting’s $3.9 billion bid for Tribune.
“Ajit Pai has the potential to be one of most consequential commissioners in the agency’s history,” said Gus Hurwitz, an assistant professor at the University of Nebraska College of Law, who is an expert in telecom policy and who supports Mr. Pai’s proposal.
Even Mr. Pai’s detractors acknowledge that Mr. Pai has been efficient at moving his agenda. Mark Cooper, a staff member of Consumer Federation of America, said Mr. Pai has far outpaced his recent predecessors.
But Mr. Cooper was also quick to criticize the moves that Mr. Pai has made.
“In every way,” Mr. Cooper said, “his decisions are bad for consumers and good for big corporations.”
Mr. Pai declined to be interviewed for this article. But in a statement, the F.C.C. said that he “has been focused on making the agency more transparent, closing the digital divide, and updating the Commission’s rules to reflect the modern communications marketplace.”
The agency added that “the F.C.C. has modernized its rules across a wide range of areas to encourage more competition and innovation.”
Mr. Pai’s deregulatory fervor began well before the presidential election and his nomination from President Trump — and comes as no surprise to those who have watched him in recent years.
The child of immigrants from India who settled in Kansas, Mr. Pai was lauded by Republicans and Democrats when he was appointed in 2011 by President Obama to the F.C.C. Lawmakers and public interest groups hoped the young nominee would bring a greater appreciation for how communications was shifting online than past commissioners.
But for five years as a minority member of the F.C.C., Mr. Pai consistently voted against regulations such as rules limiting business broadband prices and a broadband subsidy for low-income Americans. He complained that the agency’s Democratic leaders, including Tom Wheeler, were too heavy-handed on companies.
The biggest offense, in his opinion, were the 2015 net neutrality rules, which included the declaration that broadband would be subject to more utility-style rules. He said the regulations would burden the fast-growing high-speed internet market. In dissenting comments, he echoed the arguments of telecom companies that the F.C.C.’s net neutrality rules made it hard for telecoms to expand their networks, leading to less innovation in business plans and would eventually harm the economy.
He also accused the White House of presidential interference in the activities of the F.C.C., an independent agency. Mr. Pai said in his dissenting remarks in 2015 that the agency took its direction only after President Obama posted a video in favor of the net neutrality rules.
“We are flip-flopping for one reason and one reason alone,” he said at the time. “President Obama told us to do so.”
Mr. Pai’s consistent opposition attracted supporters from free-market think tanks and conservative commentators like Rush Limbaugh and Roger Stone, a former Trump adviser who recently praised the proposal to scrap net neutrality rules. He became a frequent guest on Fox News and other conservative media and was praised in the editorial pages of The Wall Street Journal.
“How fortunately ironic that it is Ajit Pai himself, as the Trump-appointed chair of the F.C.C., that will pull the plug on the ill-intended act called ‘net neutrality,’” Mr. Stone wrote recently in The Daily Caller.
Mr. Pai has been an early and active user of Twitter. But he has warned of the power of that company and others — Google, Facebook and Netflix — that compete directly with telecom and media firms.
While supporters of net neutrality argued that telecom companies wanted to become gatekeepers of the internet, Mr. Pai said the bigger threat was gatekeepers from Silicon Valley. Google, Twitter and Facebook were the gatekeepers to internet content, he said, and deprived consumers of free speech.
And even as he has used Twitter to get his message out, he has also used the company as a foil in his defiance against complaints about his decisions. He has argued that the social network suspends users who have views that run counter to those of the company.
“Let’s not kid ourselves,” Mr. Pai said last month at an event sponsored by the R Street Institute, a free markets think tank. “When it comes to an open internet, Twitter is part of the problem.”