Sen. Maria Cantwell (D-Wash.) is calling on all her constituents to fight a Federal Communications Commission action that would roll back internet protections known as net neutrality.

Cantwell made her case at a town hall in Seattle on Friday, claiming small businesses were particularly vulnerable to the policy shift because it would allow internet providers to sell different broadband speeds to different customers.

“You’re talking about a very slippery slope,” she told a Washington business owner who asked how he might be impacted by the change. “That’s why we don’t want to start. That’s why we want to have this basic protection. In my mind, you should just say to every customer that you have in your business now, ‘This is just going to make it more expensive.’ Why should we allow that when we think this is a basic service that should be available to the American people? Just get that word out to the customer base and ask people to comment.”

Cantwell is asking the public to comment on the proposal, which would roll back Obama-era protections that forbid internet service providers from slowing or prioritizing internet traffic for money or other compensation. The existing regulations make it illegal for Verizon to speed up its own streaming video site while slowing down competitors like Netflix, for example. They also forbid internet providers from selling faster service to some companies at a premium.

TechCrunch has a good explainer on how to comment on the proposal; the process is quite convoluted.

Time is of the essence, Cantwell said Friday, because the deadline to comment is Aug. 16.

“I believe that internet service should be like your telephone line,” she said. “The notion that if you have a startup and you … all of the sudden would have a fast lane or a slow lane, you’d have to pay more to be in the fast lane. It’s going to restrict capital. It’s going to slow everything down. So we definitely don’t want to see that.”

FCC Commissioner Mignon Clyburn, the only Democrat currently on the commission, echoed Cantwell’s concerns during the town hall event, which was moderated by Washington Technology Industry Association CEO Michael Schutzler.

“Net neutrality is the first amendment for the internet,” Clyburn said.

FCC Chairman Ajit Pai has been a vocal critic of net neutrality throughout his career, arguing that “the more heavily you regulate something, the less of it you’re likely to get.”

Tech titans, including Amazon, Facebook, Google, Twitter, and Netflix are planning an online “Day of Action” July 12 to protest cutting net neutrality protections.