WASHINGTON — One after another, 15 Democratic senators — nearly a third of their caucus — stepped to a microphone on Capitol Hill on Wednesday to call for tough rules to protect net neutrality.

The turnout, which included Senate Democratic leader Chuck Schumer, D-N.Y., showed they believe that they could win politically on the issue even if they ultimately fail in their long-shot attempt to reinstate the rules.

“We’re now one step away from allowing the American public to see where their elected officials stand on protecting their internet service,” said Schumer, as the Democrats formally launched an effort to restore the regulations scrapped last year by the Federal Communications Commission.

“Are they protecting average consumers and middle-class families, or are they protecting the big corporate special interests?” he asked.

Democrats collected enough signatures on a petition that forced a Senate vote to employ the Congressional Review Act, which if passed would be the first step toward overturning the FCC’s action and reinstating the rules that were designed to ensure the uninhibited flow of data online.

The 1996 act allows Congress to overturn a federal agency rule by a simple majority vote in each chamber. Signatures from 30 senators require the Senate to hold a vote that can’t be filibustered or blocked by the majority leader.

The Senate vote is expected next week and must be held by June 12 due to a time limit triggered by the publication of the FCC’s new rule in the Federal Register.

If Sen. John McCain, R-Ariz., continues to be absent because of his cancer treatment, Democrats have already secured the 50 votes needed to pass the measure with the public support of Sen. Susan Collins, R-Maine.

But supporters of net neutrality regulations, including online activists and large technology companies such as Amazon, Facebook, Google and Netflix, are making a push to secure one more vote from some undecided Republicans to ensure passage even if McCain returns.

Other Republicans and conservative activists who oppose the net neutrality regulations as heavy-handed government oversight have branded the effort a political stunt.

They said Democrats might be able to sneak the reinstatement measure through the Senate because of McCain’s absence, but it will never pass the Republican-controlled House and get signed by President Donald Trump.

“Instead of crafting forward-looking solutions that protect internet users and promote innovation, Congress will spend the upcoming days on more political theater,” Sen. John Thune, R-S.D., wrote in an opinion article on CNBC’s website Wednesday.

The rules, put in place in 2015 when the FCC was controlled by Democrats, prohibited internet service providers from selling faster delivery of certain data, slowing speeds for specific content and blocking or otherwise discriminating against any legal material.

Republicans and telecommunications companies opposed the rules.

A legal challenge was turned back by federal judges. But Trump’s election swung the FCC to Republican control and it voted 3-2 along party lines in December to eliminate the rules.

Democrats said that was a mistake and are trying to take advantage of what they said is net neutrality’s broad public support to make Republicans pay at the polls in November’s midterm elections.

Senate Democrats cited a poll by the University of Maryland’s Program for Public Consultation that found 86 percent of respondents opposed repealing net neutrality rules after a short briefing on them.

“I cannot think of an issue that polls so decisively on one side,” said Sen. Brian Schatz, D-Hawaii. “People underestimate the passion of internet voters at their peril. They are mad and they want to know what they can do, and this vote will make things crystal clear.”

jim.puzzanghera@latimes.com