Sen. Marco Rubio (R-Fla.) speaks during a campaign rally in Wisconsin in November. (Daniel Acker/Bloomberg)

Sen. Marco Rubio has been criticized by members of his own party for not doing his day job. The GOP presidential candidate rarely votes these days on legislation, for example, or makes floor speeches, or performs other duties associated with being a U.S. senator. By a close friend's admission, Rubio "hates" the Senate. But on Friday, the Florida Republican made a small effort that deserves some focus: He attached his name to a letter that attacked federal regulators over their attempts to help towns and cities set up their own, publicly run Internet providers.

"The [Federal Communications Commission] is promoting government-owned networks at the possible expense of private sector broadband providers," the letter reads. "The FCC should not be in the business of choosing winners and losers in the competitive broadband marketplace."

Rubio's renewed opposition to city-run Internet service draws greater attention to his stance on Internet policy, just as the GOP presidential candidates gear up for another televised debate. While much of Tuesday night's forum in Las Vegas will likely focus on national security, Rubio is one of the few White House contenders to have laid out a concrete position on technology issues. Should he become the GOP nominee, his views on the Internet — and how it should be maintained — will become increasingly relevant.

This isn't the first time Rubio has weighed in on public broadband; last year, he and 10 other senators, including Ted Cruz (Tex.), sent a similar letter to the FCC saying the agency risked infringing on states' rights if it helped cities like Chattanooga, Tenn., and Wilson, N.C. Those two communities operate publicly built broadband networks that compete against larger, private  providers -- such as Comcast and Time Warner Cable -- offering speeds of 1 Gbps for $70 a month.

Proponents of public Internet say those prices and speeds are far better than what private providers are willing to offer, and that the industry has pressured states to pass laws that artificially restrict their growth. The FCC moved in February to block those state-imposed limits on public networks, raising objections among industry officials and lawmakers such as Rubio and Cruz. (Notably, Cruz's name did not appear on the Friday letter to the FCC.)

Rubio's stance against a public option for Internet dovetails with his broader approach to Internet policy, which can be summed up in two points: Limit Washington's power over communications providers, and transfer federally owned airwaves to private wireless carriers so that they can upgrade their mobile Internet networks. He opposes the FCC's decision to regulate Internet providers with telephone-style rules, under net neutrality. And he wants government agencies to give up more spectrum — the stuff that carries your cellphone calls and data — to companies without restrictions or conditions.

Rubio laid all this out in a 2013 speech to the conservative Free State Foundation, a Washington think tank. Analysts said the speech hewed closely to the positions of large, incumbent telecom and cable companies, a sign that a Rubio presidency would be good for those industries.

Hinting at his foreign policy strategy, Rubio's speech outlined a "growing international threat" to the Internet in countries such as China. He drew parallels between Beijing's restrictions on Internet search and expression on the one hand, and moves by the FCC to treat U.S. Internet providers more skeptically on the other.

"We cannot stand idly by as countries try to justify censorship or economic regulation of the Internet," he said. And Rubio made sure to cast his positions as beneficial to the middle class.

All this might sound like pretty standard Republican fare: less government, more help to the private sector. But as some point out, in this election cycle, "standard" has largely gone out the window. With the rest of the field preoccupied with immigration and terrorism, it's hardly clear what any of the candidates think about the Internet — a sector of the economy that now employs roughly 3 million Americans and accounts for 6 percent of the nation's GDP.

Rubio's 2013 address "is the most comprehensive speech on communications policy issues by any presidential candidate by either party," analysts at New Street Research wrote in a recent note to investors. "And in that sense, [it] sets out as much of map on our space as we are likely to see."