As President Trump rushes to dismantle Obama-era rules that protect Americans, he has an energetic helper over at the Federal Communications Commission. Its new Republican chairman has started undoing policies of his predecessor that were intended to make phone, cable and internet service more fair and more affordable.

Ajit Pai, who was a commissioner before he became chairman last month, is trying to wipe away net neutrality rules put in place by Tom Wheeler, the former chairman, to prevent broadband companies from creating fast and slow lanes on the internet. Mr. Pai has scrapped a proposal to let people buy cable-TV boxes instead of renting them at inflated prices from companies like Comcast. Many of Mr. Pai’s moves would hurt the people who have the least power. For instance, he has backed away from rules to lower the exorbitant rates for prison phone calls. And he has suspended nine companies from providing discounted internet service to poor people through a program known as Lifeline.

Mr. Pai, who says the Wheeler-era regulations are burdensome, clearly favors policies that serve the interests of large telecommunications companies.

Consider the net neutrality rules, which were put in place to prevent broadband companies from giving preferential treatment to content from their affiliates or business partners. Because only one or two cable and phone companies provide high-speed internet access to homes in most of the country, they can easily impose abusive policies without fear of losing customers. Those businesses have tried to use their power as internet gatekeepers to demand that streaming companies like Netflix pay them fees to deliver movies and TV shows to people who are already paying for broadband. The regulations were upheld last year by the United States Court of Appeals for the District of Columbia. If Mr. Pai now scraps them, he will be helping big telecom companies at the expense of internet users and smaller companies without the deep pockets to pay broadband providers.