It’s been six months since FCC chairman Ajit Pai officially began the rollback of the Title II net neutrality order — and progress has been slow. The new rules finally entered the federal register in February, and they’re already facing a number of legal challenges. While some net neutrality advocates dig in for a prolonged court battle, there’s a separate front opening up in Congress that could prove far more effective. On May 16th, the Senate will vote on a Congressional Review Act resolution to roll back Pai’s order completely. It’s a long shot, but if it works, it would be faster and more effective than any court ruling, completely restoring Wheeler’s 2015 order.

The plan relies on some unusually arcane congressional procedure, so we’re running down all the biggest questions around Markey’s plan and laying out exactly what it would take for Congress to reinstate net neutrality.

We have the signatures. On May 9th, we officially file the petition to force a vote on the Senate floor to save #NetNeutrality.

#OneMoreVote pic.twitter.com/BvxnTjGwx5 — Ed Markey (@SenMarkey) April 30, 2018

What is the Congressional Review Act?

Passed in 1996, the Congressional Review Act (or CRA) gives Congress the power to reverse any federal regulation by passing a joint resolution of disapproval within 60 legislative days of enactment. In practice, that means a majority in Congress can undo any rules set by the executive branch, provided they act quickly enough. Crucially, a successful CRA vote blocks any future consideration of the rule, so the agency can’t just pass the same rule again and hope it goes through this time.

You might recall the CRA from when the Republicans used it to undo late-breaking Obama-era regulations like the Stream Protection Rule and the FCC’s own internet privacy rules. Now, internet groups want to use the same rules to undo Pai’s order, restoring Wheeler’s net neutrality order as the law of the land. As far as the CRA is concerned, Pai’s order is a regulation like any other, and the same procedure can be used to undo it.

How can Democrats do this without controlling Congress?

It’s hard to get anything through Congress without the approval of the Republican majority, which controls the committees and the broader schedule. But a CRA motion isn’t technically a bill, so it plays by slightly different rules. Senators can force a vote to be scheduled in their chamber by submitting a petition signed by just 30 members, which is exactly what Sen. Markey (D-MA) did on May 9th.

Crucially, the CRA also lets senators sidestep the traditional filibuster, requiring only a bare majority instead of the 60 votes increasingly needed to pass legislation through the chamber. Advocates say they already have 50 votes confirmed — all 49 Senate Democrats, plus Sen. Susan Collins (R-ME) — and eyes are on Sen. John Kennedy (R-LA) or Sen. Dean Heller (R-NV) as a possible 51st. If either flips, the resolution will easily make it through the Senate.

When does the Senate vote?

Right now, the Senate vote is scheduled for the 16th, most likely late in the day. That’s when we’ll find out if the resolution moves forward and if any other Republicans are willing to break ranks. If not, net neutrality advocates have to go back to the drawing board.

“May 16 will be the most important vote for the internet in the history of the Senate,” Sen. Markey said in a statement, “and I call on my Republicans colleagues to join this movement and stand on the right side of digital history.”

What happens if the resolution passes the Senate?

Things get harder from here. There’s a similar mechanism for forcing a vote in the House, but it requires a full majority of representatives in support, and it’s not clear whether Markey’s resolution has the votes. Assuming total Democratic support, reaching a majority would mean peeling off 25 House Republicans, many of whom may be reluctant to vote against their party. It’s also worth remembering that not all Democrats necessarily support net neutrality. Without sustained public pressure, many may prefer to leave Pai’s rule in place and not have to risk a backlash from telecoms.

Still, we’re likely to find out. A House discharge petition is expected to be made public shortly after the resolution is submitted, and members will have until the end of the session in January to corral a majority of representatives to sign on.

It helps that net neutrality is still extremely popular. A poll in December found more than 80 percent of Americans support keeping the Wheeler rules in place. More importantly, support wasn’t polarized: 75 percent of Republicans approved of the rules, compared to 89 percent of Democrats. Unlike health care or gun control, net neutrality has never been a base issue for either party, so the votes may not break down along party lines. As we head into what could be a brutal midterm election for Republicans, it’s easy to imagine Republicans breaking ranks to appeal to swing voters, particularly if neutrality supporters make their voices heard.

Could Trump veto the whole thing?

Even if it manages to make it through Congress, the CRA resolution would have to pass the president’s desk where it would face even steeper odds. President Trump has to sign the resolution before it takes effect, and if he vetos it, the entire effort would stop right there. While Trump’s public statements on net neutrality have been a bit confusing, it’s safe to say the president opposes the Wheeler rules and supports Pai’s efforts to repeal them. And unlike members of Congress, Trump hasn’t been particularly swayed by mass public sentiment or the desire to help his fellow Republicans win elections, so it’s hard to think what would push him to change his position here.

But even if Trump ultimately blocks the CRA effort, simply getting it to his desk would be a significant show of force for net neutrality advocates. The last 20 years of FCC action on the issue have been about warring interpretations the Communications Act, but both sides are increasingly looking to settle the issue with new legislation. If Congress votes to uphold the Wheeler rules, that’s a strong indication that whatever new law gets passed should look like the Title II rules Wheeler put in place, even if we have to wait for a new president and a new Congress to actually pass it into law.

Of course, the only way any of this will happen is as a result of sustained political activism, which neither side should take for granted. The Markey resolution is the result of intense political pressure in the wake of the Pai order, which forced senators to line up over an issue that’s otherwise easy to ignore. Getting the House in line would take a similar push, and even more sustained mobilization — some of which is already planned, through efforts like the upcoming Red Alert campaign. But with Pai’s rules still looming and the full repeal within sight, that mobilization may be the best chance we have to keep net neutrality rules in place.

Update 5/14 11:07AM ET: This article has been updated to reflect the successful scheduling of a Senate vote.