With a global climate deal under negotiation in Paris, the Republican-led US Congress on Tuesday is expected to repeal White House regulations on reducing greenhouse gas emissions, a move certain to spark President Barack Obama's veto.
Votes to block a pair of Environmental Protection Agency (EPA) rules that limited carbon dioxide emissions from existing and new US power plants were due in the House of Representatives, after the measures passed the Senate last month.
Their approval by the House would deal a harsh rebuke to Obama as he heads home from a visit to France for the start of the UN climate summit.
The EPA rules incensed Republicans including Senate Majority Leader Mitch McConnell, who is from the coal-producing state of Kentucky, when the White House announced Obama's Clean Power Plan in August.
They argue that the economic cost of the endeavor, particularly in coal mining states, would cripple industry and hike energy costs for millions of Americans.
Under the rule, the power sector's carbon dioxide emissions will have to be cut by at least 32 percent below 2005 levels by the year 2030.
The far-reaching regulations form a core of Obama's efforts to reduce overall US greenhouse gas emissions, as negotiators gather in Paris seeking to craft a historic global deal to tame global warming.
Many conservatives in the US Congress deny that climate change is a result of human industry and agriculture, and have opposed emissions controls designed to slow global warming.
McConnell has accused Obama of seeking to implement his Clean Energy Plan "by executive fiat," and has warned that the result could be the elimination of 250,000 jobs and higher energy costs in more than 40 states.
He noted on Sunday that half the states have sued to try to halt the plan, and "the next president could tear it up."
The White House has said Obama would veto the measures if they pass. Congress does not appear to have sufficient votes to override the veto.