With only a week to go before the 2014 midterm elections, polling from key battleground states indicates a small but widening advantage for Republicans. A six-seat net gain in the Senate would put both chambers of Congress under GOP control, uniting the two houses in opposition to many of the hallmark policies of the Obama presidency, including rules to curb carbon emissions from the nation's power sector.
Whether a Republican Senate could seriously imperil the president's Climate Action Plan, as the party's leadership has promised to do, is another matter.
Both House Speaker John Boehner (R-Ohio) and Senate Minority Leader Mitch McConnell (R-Ky.) have indicated in the past several months that climate regulation proposed by U.S. EPA, and specifically the Clean Power Plan (CPP), would be a prime target if Republicans gain control of the Senate. Both responded to the CPP's proposal in early June by proposing legislation to curb or weaken the rule, although those proposals died in the Senate.
But even if Republicans take the Senate next week, the leadership's ambitions will likely run up against the basic math of the legislative process. If Republicans pick up the six seats they need to gain control of the Senate, they'll still be shy of the three-fifths majority needed to override filibusters by Democrats.
And while enough coal-state Democrats might conceivably be swayed across the aisle to beat a filibuster on climate regulation, "it's hard to think of a plausible scenario where you end up with a [two-thirds] supermajority" needed to override a presidential veto, said Nathan Richardson, an assistant professor at the South Carolina School of Law.
Budget wars, round 2?
Congress has the power to challenge the CPP directly, either through the Congressional Review Act -- which allows Congress to overturn recent regulation from federal agencies -- or by an amendment to the Clean Air Act. Assuming such measures are able to pass through both chambers in the future, however, there's little chance they would make it across Obama's desk without a veto.
Instead, the Republican leadership has indicated that it will pursue a less direct line of attack, by attaching riders to major spending bills that the government needs to pass in order to operate. In comments made to conservative donors at an event in June, later made public by The Nation, McConnell pointed out that, with both chambers secured, Republicans would "own the budget."
"That means that we can pass the spending bill," he said. "And I assure you that in the spending bill, we will be pushing back against this bureaucracy. ... We're going to go after them on health care, on financial services, on the Environmental Protection Agency, across the board."
Congress could pass appropriations riders to larger spending bills that would bar EPA from carrying out its rule, or deny it the funds it would need to do so. But again, Obama is unlikely to allow any law that undercuts the viability of his central piece of climate regulation, or significantly lowers its emissions-reduction targets, said Thomas Lorenzen, a partner with law firm Dorsey & Whitney who previously defended EPA regulations for the Justice Department.
"At this stage, the president is not going to give up any of his climate commitments," he said. "I think Obama sees this as not only critical for this country, but critical to driving other countries to satisfy their own obligations. If he sends a signal that the U.S. is willing to step back, that would send the wrong message overseas."
A spending bill with riders designed to undercut EPA could set the scene for another budget showdown, similar to confrontations last year over the Patient Protection and Affordable Care Act. The reputations of both parties suffered from that episode. But Republicans may bet on the public's ire falling primarily on Obama if a major spending bill dies on his desk, said Lorenzen.
Change of atmosphere, but not action
Whether or not confrontations over regulation lead to a high-stakes showdown, a Republican victory in the Senate would signal a change in atmosphere as EPA advances its proposed rule.
Sen. James Inhofe (R-Okla.), one of Washington's most vociferous climate skeptics, is next in line for the chairmanship of the Senate Environment and Public Works Committee. Sen. Lisa Murkowski (R-Alaska) would take the lead role in the Senate Energy and Natural Resources Committee, while Sen. Ted Cruz (R-Texas) has a shot at the chairmanship of the Subcommittee on Science and Space.
"Should Republicans take the Senate, the character of Congressional oversight will change," wrote Scott Segal, head of the Policy Resolution Group at law firm Bracewell & Giuliani, in an email. "It is likely that regular order will return to the appropriations process, meaning that provisions which could alter or delay the rule are likely to have more thorough airing."
"Further EPA has not been forthcoming with documents it relied upon to formulate its rule," he added. "You can expect significant additional pressure from the Congress to release and explain the actual basis of the rule."
Calling EPA officials forward to testify before committees or requesting additional documentation may bring added visibility to the CPP, including areas where the rule may be challenged later in the courts. But as far as major congressional action against the rule is concerned, precedent speaks to the negative, said Paul Bledsoe, a senior energy fellow at the German Marshall Fund who served previously on the White House Climate Change Task Force under President Clinton.
"Historically, the abilities of narrow congressional majorities to inhibit [executive] rulemaking authority have been less than marginally effective," he said. "It doesn't matter whether it was Republicans pushing back at fuel economy standards under Clinton or Democrats during the Bush years -- it ends up being a great deal of posturing."