The FCC is set to publish this week its order to repeal net neutrality rules established under President Obama, setting off what is likely to be a flurry of lawsuits and starting a countdown toward possible lawmaker action.

In December, the Republican-majority Federal Communications Commission voted 3 to 2 to scrap rules that bar internet service providers from blocking, slowing or favoring certain online content over others.

The Federal Communications Commission will officially publish the order in the Federal Register on Thursday, setting off a 60-day window for Congress to pass a resolution to overturn it.

The Senate is one vote shy of the needed 51 votes to use the Congressional Review Act to block the FCC order. In the House, the effort has 111 of the 218 needed co-sponsors, according to a tally on Jan. 23.

When reached for comment Wednesday, FCC Chairman Ajit Pai’s office referred us to the Federal Register’s website, which confirms that “Restoring Internet Freedom” is set to be published Thursday. Reuters and the Hill had cited unnamed sources in earlier reports.

Advocacy groups are planning a day of action Tuesday to put pressure on lawmakers to support the push to overturn the order.

“The CRA is the clearest path to restore net neutrality protections that never should have been taken away in the first place,” said Evan Greer, campaign director for Fight for the Future, in a statement this week. The groups are asking supporters to “flood” lawmakers with calls, emails and tweets on Feb. 27.

Get tech news in your inbox weekday mornings. Sign up for the free Good Morning Silicon Valley newsletter.

If the Congressional effort fails to overturn the FCC order, legal battles are certain. Nearly two dozen state attorneys general, including California’s, kicked off the lawsuits against the FCC last month. Mozilla, maker of the Firefox browser, and public advocacy groups also sued last month while acknowledging that they knew they were supposed to wait till 10 days after the order’s official publication.

Related Articles California, 21 other states sue FCC over net neutrality repeal

50 senators endorse resolution to restore FCC net neutrality regulations More lawsuits are sure to follow, especially since the Internet Association — whose members include tech’s biggest companies — announced in January that it plans to join the legal efforts to fight the FCC’s order. Wednesday, the Computer & Communications Industry Association announced that it, too, plans to intervene.

In addition, some individual states have either mandated or are considering their own net neutrality rules. The California State Senate late last month passed one such bill.

This post has been updated to reflect confirmation of the scheduled publication of the order.