FCC Chairman Thomas Wheeler (Andrew Harrer/Bloomberg)

On Tuesday, the nation's top telecom regulator told House lawmakers what consumer advocates have been longing to hear for weeks: that the Federal Communications Commission could move to block the rise of Internet fast lanes.

FCC Chairman Tom Wheeler said the agency recognizes that Internet providers would be disrupting a "virtuous cycle" between the demand for free-flowing information on one hand and new investment in network upgrades on the other if they started charging companies like Google for better access to consumers. What's more, he said, the FCC would have the legal authority to intervene.

Post tech reporter Hayley Tsukayama explains the idea of net neutrality and why its future could affect every Internet user. (Davin Coburn/The Washington Post)

"If there is something that interferes with that virtuous cycle — which I believe paid prioritization does — then we can move against it," Wheeler said, speaking loudly and slowly.

A little later, in response to a question from Rep. Henry Waxman (D-Calif.), Wheeler cited network equipment manufacturers who've argued that you can't create a fast lane without worsening service for some Internet users.

"That's at the heart of what you're talking about here," Wheeler said. "That would be commercially unreasonable under our proposal."

The FCC has not settled on whether to establish an outright ban on paid prioritization; its proposal asks the public whether the commission should take that step. But Wheeler, who has hinted at his support for a case-by-case approach rather than a blanket ban, could view any paid prioritization deal with much more skepticism than net neutrality advocates are expecting.

The question then is: If paid prioritization is considered improper under the FCC's net neutrality rules, is there any prioritization that would still be allowed?