Federal regulators have set a new definition for broadband that establishes 25 megabits per second as the baseline for high-speed downloads, up from 4 Mbps previously.

With this standard, the Federal Communications Commission will be able to argue for much stronger action on Internet providers — a point that's rankling Republicans on the commission as the agency moves to promote the adoption of fast, cheap and reliable Internet in America.

It's a simple accounting change that will have major ramifications. As a result of the decision — which also sets the minimum speed for uploads at 3 Mbps — millions of people who subscribe to slower plans will effectively lose their broadband status. Combine those with the substantial share of Americans who have never had broadband, and as many as 17 percent of America, or 55 million people, will lack access to high-speed broadband under the new measure, according to the FCC.

Conservatives are decrying the move as a case of government overreach, calling the 25/3 Mbps standard an "arbitrary" threshold and arguing that most consumers seem to think the old one — 10 Mbps down, 1 Mbps up — works just fine.

"Seventy-one percent of consumers who can purchase fixed 25 Mbps service — over 70 million households — choose not to," said Republican FCC Commissioner Ajit Pai.

For an agency whose mission is to remove barriers to broadband, the FCC is its own worst enemy, Pai added, saying the FCC is intentionally finding that the industry has failed just so that it can "regulate it back to health."

But Democrats on the commission say the new standard establishes a forward-looking, aspirational target. Those who lack access to speeds that are "table stakes" for the rest of the country don't deserve to be left behind, they argue. FCC Chairman Tom Wheeler pointed out that subscriptions to 25/3 service have quadrupled in the last three years. And Wheeler said that Internet providers' claims that there isn't enough demand for 25 Mbps broadband isn't borne out by their marketing campaigns, which treat customers like voracious data consumers.

"Someone is telling us one thing and telling consumers another," Wheeler said. "Our challenge is not to hide behind self-serving lobbying statements, but to recognize reality. And our challenge is to help make that reality available to all."

As the FCC prepares to intervene next month against state laws that make it harder for cities to build their own, public alternatives to traditional Internet providers — and as it plans to release its latest draft rules to prevent discrimination against Internet traffic — the standard for broadband will become a key political tool in defending the FCC's actions. So will the underlying law that recognizes the FCC's authority to promote broadband, Section 706 of the Communications Act. A Republican-backed bill in Congress is already seeking to strip the FCC of that power.