Under the Congressional Review Act, any regulation finalized within 60 legislative days of the end of a presidential term can be overturned with a simple majority vote in the Senate.
Before 2017, the review act procedure had been used only once, to undo a Clinton-era rule on workplace ergonomics in 2001. Then, in the early months of the Trump administration, Senate Republicans used the procedure to wipe out 14 Obama-era regulations in 16 weeks. Democrats now intend to employ it to wipe out some of the executive-branch policies enacted in the last days of the Trump administration.
The most significant of those would be the rules on methane, which were published by the Environmental Protection Agency. While most climate change regulations target carbon dioxide, the most damaging greenhouse gas, methane is a close second, lingering in the atmosphere for a shorter period of time but packing a bigger punch while it lasts. By some estimates, methane has 80 times the heat-trapping power of carbon dioxide in the first 20 years in the atmosphere.
For Democrats to repeal the methane rule, they will most likely need all 50 votes of their party’s razor-thin majority — including that of Senator Joe Manchin III of West Virginia, who often votes with Republicans on matters of environmental policy. However, in 2017, Mr. Manchin voted with his party to retain a different regulation on methane pollution.