Amid all the hoopla surrounding Obama's upcoming speech on climate policy, it's worth keeping this in mind: it doesn't make Gina McCarthy's nomination to head the Environmental Protection Agency any easier.

McCarthy, who heads EPA's air and radiation office, has a history of working with industry and Republican officials to broker compromises on air pollution rules. But that hasn't been enough to win over some key Republican senators, who have portrayed her as the embodiment of Obama's left-leaning environmental policy.

Now that the president is proceeding with regulating greenhouse gas emissions from existing power plants, Senate Republicans are likely to be even tougher on McCarthy, who informed them in April the agency was not drafting such regulations.

In responses submitted April 30 to the Senate Environment and Public Works Committee's top Republican David Vitter (La.), McCarthy made the point three times, in almost exactly the same phrase: "EPA is not currently developing any existing source GHG regulations for power plants," she wrote, referring to greenhouse gas emissions.

To be clear, there's no reason to assume McCarthy's reply wasn't technically accurate. But now that EPA is poised to embark on this path, it's not going to endear her to Republicans.

Stephen Brown, vice president for government affairs for Tesoro Corp., a major oil refiner, puts it this way. In addition to affecting the nation's economy, he wrote in an e-mail, "I guess they are kissing Gina McCarthy "goodbye" with this announcement as well."

However a senior administration official, who asked not to be identified, said congressional Republicans should judge McCarthy on her overall record, rather than a single policy the administration is pursuing.

“Gina McCarthy is uniquely qualified to lead the EPA. She has decades of experience, serving both Republicans and Democrats," the official said. "She has a long track record working with industry and business leaders to find common sense solutions. The Senate should confirm her without delay.”

And McCarthy's opponents might want to keep one other factor in mind--as head of the air and radiation office, McCarthy is in charge of writing the rules for power plants right now. So blocking her elevation may do little to change the shape of any new climate regulation coming out of EPA in the months to come.