"Every time the government has examined the broadband market ... it concludes the broadband market is competitive and that we should be wary of new rules," said Commissioner Robert McDowell, a Republican, who opposed the plan.
"Preserving the open Internet is non-negotiable. It is open today," said Meredith Attwell Baker, the other Republican commissioner on the panel. "Government action is not needed to preserve it. This decision is being made because we want to, not because we need to."
The plan had also been derided from the left for being too watered down, amounting to a giveaway to corporations. But both of Genachowski's Democratic colleagues on the five-member FCC supported the plan, despite reservations.
Commissioner Michael Copps, a Democrat, said the new rules "could represent an important milestone in the ongoing struggle to safeguard the awesome opportunity-creating power of the open Internet."
One quirk of the FCC is that the agency does not release to the public exactly what is being brought to a vote. The full text of the new rule won't be available to the public for several more days.
But Genachowski outlined his principles in a speech earlier this month, declaring the coming rule "an important milestone in our effort to protect Internet freedom and openness."
"The FCC is moving the ball forward," said Consumers Union policy counsel, Parul P. Desai, said in a statement.
ABC News' Brian Hartman contributed to this report.