Fifty senators have signed on to legislation that aims to overturn the Federal Communication Commission‘s (FCC) decision to rescind net neutrality rules—leaving them in need of just one Republican senator to pass their effort.

The Senate is trying to pass a resolution of disapproval through the Congressional Review Act (CRA) to overturn the FCC’s vote in December to gut net neutrality rules, which ensured that internet service providers (ISPs) must treat all internet traffic equally. Critics fear that without the rules ISPs could “speed up” or “slow down” certain websites—for example, slowing down Netflix in favor of an ISP-led streaming service.

Shortly after the vote, Sen. Ed Markey (D-Mass.) and 15 other senators said they planned to use the CRA to undo the FCC’s vote. On Monday, Senate Democrats said they had 50 votes in favor of their CRA, leaving them just one vote shy of passing it, the Washington Post reports. Sen. Susan Collins (R-Maine) was the first Republican to sign onto the effort. Collins had previously voiced her opposition to the FCC’s vote.

“With full caucus support,” Senate Minority Leader Chuck Schumer (D-N.Y.) told the Post, “it’s clear that Democrats are committed to fighting to keep the Internet from becoming the Wild West where ISPs are free to offer premium service to only the wealthiest customers while average consumers are left with far inferior options.”

In order to overturn the FCC’s net neutrality decision, the Senate will have a full vote on the resolution, followed by the House of Representatives. President Donald Trump would also need to sign the resolution into law.

Last week high-profile Democrats publicly endorsed net neutrality, with some suggesting the vote on the CRA will be used as a political tool during the 2018 midterms to show who was in favor of net neutrality. Making net neutrality a campaign issue could be politically rewarding for Democrats, as some polls suggest that more than 75 percent of Americans believe the FCC’s vote gave “ISPs a license to steal from consumers.”

A website set up by several internet advocacy groups that allows people to contact their lawmakers to voice their support for the CRA vote has driven more than a million calls to Congress.

“Net neutrality is going to be an election issue in 2018 and every member of Congress knows it,” Evan Greer, campaign director of internet advocacy group Fight for the Future, said in a statement. “The CRA is steamrolling through the Senate because lawmakers are reading the writing on the wall that it’s the only viable legislation on the table.”

You can read the Washington Post report here.