WASHINGTON — When Congress voted to overturn internet privacy rules last month, the swift action by Republican lawmakers sent a clear message: They were just getting started.

The next target is net neutrality, which is the guarantee that all internet content is equally accessible. That could be followed by cuts in broadband subsidies for low-income households and a relaxation in rules preventing media consolidation in local markets.

Republican regulators and lawmakers have been waiting for this moment. Coordinating across the government, they are putting several telecommunications and technology policies created during the Obama administration on the chopping block. Already, Ajit Pai, the Republican chairman of the Federal Communications Commission, who was appointed to the agency by President Barack Obama and named to lead it by President Trump, has begun chipping away at the low-income broadband subsidy and net neutrality rules created by his Democratic predecessor.

“There was a good bit of overreach by the past F.C.C. that caused a lot of confusion,” said Representative Marsha Blackburn, Republican of Tennessee, who was vice chairwoman for President Trump’s transition. “We are going to have technology and telecommunications policy that is light touch.”

In a major philosophical shift from the Obama administration, Republican leaders have said they will look for proof of harm before creating new regulations for telecom firms. They believe antitrust and consumer protection laws suffice for government oversight of the sector.

“The F.C.C. needs a more evidence-based approach,” said Roslyn Layton, a fellow at the American Enterprise Institute who was on Mr. Trump’s F.C.C. transition team. “No one is writing in and asking for Title 2 reclassification of broadband. Consumers are complaining about unwanted calls and billing problems.”

The changes have been a boon for telecommunications and cable firms that had for years fought unsuccessfully against a Democratic-led F.C.C.

They have cheered Mr. Trump’s decision to renominate Mr. Pai after his term ends in June. They want to overturn net neutrality and other rules so they can start offering new business plans that consumer groups have protested.

“The repeal of net neutrality would be a clear positive for broadband network providers,” analysts at Pacific Crest Securities wrote in a research note after the election. Internet service providers “would be able to charge for access to the network and for ‘fast lanes,’ which would increase potential monetization.”

Momentum is with the Republicans. Last month, they voted to overturn privacy rules (scheduled to take effect later this year) that required internet service providers like AT&T and Comcast to get permission from a customer before tracking and selling data browsing and app activity. Mr. Trump signed the measure on April 3.

Lawmakers said the F.C.C.’s rules were much stricter than any privacy requirements placed on web firms like Google and Facebook. They argued that the privacy watchdog duties should fall to the Federal Trade Commission, which does not have strong privacy regulations but requires companies to self-police the privacy policies they promise to customers.

Republicans lawmakers moved against the privacy rules under the Congressional Review Act, a procedure used to overturn new agency rules.

The lawmakers say their next target is the F.C.C.’s declaration in 2015 that broadband should be treated like a common carrier service, such as the phone. That utility-like categorization strapped new rules on broadband providers.

The F.C.C. chairman and lawmakers have promised to undo those rules soon. Ms. Blackburn said in an interview that the F.C.C. will likely create an order to overturn them.

Democrats and consumer groups have protested, saying the internet has become essential for work, education and commerce, and needs greater oversight.

“The recent weeks are prologue, and I am fearful that we are moving in a direction that will unravel and undo some incredible gains we’ve made for consumers,” said Mignon Clyburn, the sole Democratic commissioner at the F.C.C.

The reclassification of broadband also served in 2015 as the foundation for the F.C.C.’s net neutrality rules, which ban broadband providers from blocking or slowing down of traffic on the internet. Google, Facebook and Netflix have been the strongest corporate backers of net neutrality, but smaller start-ups could be most affected.

Without strong net neutrality rules, an internet service provider like Verizon or Charter could give preference to certain content, making it harder for an independent streaming service like Vimeo to compete.

An example is AT&T’s free service offering mobile streaming of DirecTV videos to customers that does not count against data limits. Consumer groups have balked, saying the practice puts competing video providers at a disadvantage because their videos do count against those customers’ monthly data limits.

Mr. Pai has already signaled his approval of such “zero rating” programs, saying they did not appear to violate net neutrality — and that they are popular with consumers. In January, he closed an investigation into zero-rating promotional streaming programs by AT&T, Verizon and T-Mobile.

But net neutrality will not be easy to undo. A federal appeals court upheld the regulations last year in a case brought by Verizon, Comcast, AT&T and other internet service providers. Congress could try to overturn the rules but could not use the Congressional Review Act to do so because net neutrality was created more than a year ago.

Republicans will also look for ways to cut fat in programs they deem wasteful or abused. One target could be the Lifeline broadband subsidy for low-income households. Mr. Pai prevented nine providers from offering the subsidy weeks into his role at the F.C.C.

He has also pointed to longtime media ownership rules that prevent a local TV station from also owning a newspaper in the same town. F.C.C. rules also prevent sharing of resources between TV stations. Mr. Pai has said the convergence of tech and media have made such rules too outdated. Companies like Netflix and Google are a bigger threat to broadcast television stations than media consolidation, Mr. Pai said.

The greatest uncertainty surrounds telecom and tech mergers. AT&T’s proposed $85 billion merger with Time Warner is being reviewed by antitrust officials at the Justice Department. Republicans are expected to be generally more permissive of mergers, but Mr. Trump remains the wild card.

The president has said he would not allow the merger, and analysts say his complaints about news coverage by CNN, which is owned by Time Warner, could complicate the approval. But Attorney General Jeff Sessions has said he would not be influenced by politics in decisions at the agency.

“This will be the first big test,” said Bradley Tusk, who leads the investment firm Tusk Ventures. “If you aren’t in Trump’s wheelhouse, expect to get a more traditional Republican look at mergers.”