In a rare senatorial act, full-time Republican presidential candidate Marco Rubio joined with a handful of fellow legislators on Friday in an attempt to block local municipalities from undercutting big telecom companies by providing cheap, fast internet service.

Rubio, who is raising campaign cash from the telecom industry for his presidential campaign, fired off a letter to the Federal Communications Commission asking the agency to allow states to block municipal broadband services.

The letter was the latest salvo in a long-running effort by the major telecom companies to outlaw municipal broadband programs that have taken off in cities such as Lafayette, Louisiana, and Chattanooga, Tennessee, because they pose a threat to a business model that calls for slow, expensive internet access without competition.

In Chattanooga, for instance, city officials set up a service known as “The Gig,” a municipal broadband network that provides data transfers at one gigabit per second for less than $70 a month — a rate that is 50 times faster than the average speed American customers have available through private broadband networks.

AT&T, Cox Communications, Comcast, and other broadband providers, fearing competition, have used their influence in state government to make an end-run around local municipalities. Through surrogates like the American Legislative Exchange Council, the industry gets states to pass laws that ban municipal broadband networks, despite the obvious benefits to both the municipalities and their residents.

That’s why the FCC has become involved. The agency stepped in to prevent states from crushing municipal broadband and released a rule this year that allows local cities to make the decision on their own.

As a result, telecom companies are furiously lobbying the FCC, litigating the rule in court, and leaning on GOP lawmakers to pressure the agency to back down. As the Daily Dot reported, the letter released by Rubio and other senators expresses “serious concern” about the FCC rule. “The FCC is promoting government-owned networks at the possible expense of private sector broadband providers … who have made strides to deploy networks throughout the country,” Rubio and seven other Republican senators wrote.

Rubio’s presidential campaign has relied heavily on AT&T lobbyist Scott Weaver, the public policy co-chair of Wiley Rein, a law firm that also is helping to litigate against the FCC’s effort to help municipal broadband. As one of Rubio’s three lobbyist-bundlers, Weaver raised $33,324 for Rubio’s presidential campaign, according to disclosures.

Rubio’s campaign fundraising apparatus is also managed in part by Cesar Conda, a lobbyist who previously served as Rubio’s chief of staff. Registration documents show that Conda now represents AT&T.