Gina McCarthy, the Environmental Protection Agency's assistant administrator for the Office of Air and Radiation, was once Mitt Romney's "green quarterback" — a top official in the former Massachusetts governor's Executive Office for Environmental Affairs. She also ran Connecticut's Environmental Protection Department under Republican Gov. Jodi Rell. So when President Obama picked her to be the next head of the Environmental Protection Agency on Monday, it may have surprised some political observers to see a fierce backlash from conservative groups.

Let's begin with a statement from the American Energy Alliance, a conservative energy policy think tank:

The EPA will look as different under Gina McCarthy as Cuba looked when Uncle Fidel passed the hammer and sickle to his little brother Raul. [Politico]  

Not a great start for McCarthy's confirmation hopes! National Review's John Fund doesn't have a high opinion of McCarthy either, calling her the "point person for the administration’s 'war on coal' campaign," and knocking her "superficial credentials as a moderate." 

How about actual lawmakers in Washington? Sen. David Vitter (R-La.) and Rep. Lamar Smith (R-Texas), who sits on the House Committee on Science, Space and Technology, sent a joint letter to McCarthy claiming she "and other high-ranking administration officials have repeatedly backtracked and reneged on promises to Members of Congress to make the scientific information that underpins the Agency’s basic associations between air quality and mortality available to the public and independent scientists over the last year and a half."

Why are conservatives so mad about McCarthy? Probably because, as the Washington Post points out, "McCarthy will face a staggering number of regulatory decisions in the upcoming term," and "with Congress deadlocked, it’s likely that many of these EPA rules will be the only action the Obama administration takes on global warming this term." In other words, McCarthy could be Obama's only ally capable of making substantive changes to U.S. environmental policy. 

Another factor that won't endear McCarthy to Republicans is her old boss, former EPA chief Lisa P. Jackson, who was vilified for creating supposedly "job-killing regulations," mostly related to defining carbon dioxide as a pollutant under the Clean Air Act. Republicans also pushed for an official inquiry into a secondary email account Jackson used to communicate within the EPA.

So put on your seatbelt — McCarthy's road to confirmation may not be as bumpy as Chuck Hagel's, but don't expect it to be super smooth either.