The Republican presidential primary has grown increasingly hostile, with the ad hominem attacks consistently buoyed by policy differences.

One area in which just about all the GOP candidates seem to agree, however, is the need to rein in the regulatory reach of the Environmental Protection Agency. Gov. John Kasich, Ohio, has said the EPA should not regulate carbon emissions and Sen. Ted Cruz, Texas, promises in virtually every speech he makes to undo the new environmental rules instituted throughout the Obama administration on day one.

Cruz has called Obama’s EPA “lawless and radical,” adding regulations such as the Clean Power Plan would “destabilize the nation’s energy system.” The firebrand senator called the administration’s “dangerous agenda” unconstitutional.

He also deplored EPA’s Waters of the United States rule last month.

“They're hurting from a federal government whose policies have been making it harder and harder for farmers to survive,” Cruz said at a CNN town hall. “They're hurting from an EPA who is imposing massive burdens on farms.”

Even frontrunner Donald Trump, typically seen as shying away from hard policy proposals, has pointed to what he views as EPA overreach as detrimental to American businesses (though Trump does struggle to remember the name of the agency).

So how does Gina McCarthy, administrator of the agency on the receiving end of universal Republican animosity, repond? Not so fast.

McCarthy said her regulations are “grounded in the law.”

"The one thing I know more than any other agency is EPA's rules get scrutinized like no other,” the administrator said this week, as reported by The Washington Examiner. “They would have to go to that same level of scrutiny by any president should there be a reverse in direction.”

To follow through on their promises to undo virtually every regulation the EPA has issued in the last seven years would require a drawn out legal battle, she said. You would need a clear record to establish that or you will be working through the court system for a very long time," McCarthy said. The EPA’s Clean Power Plan hangs in the balance at the Supreme Court.

She added the rules were based in authority granted by Congress.

“They're not decisions that a president can come in and express an opinion and have those decisions go away,” McCarthy explained.

Even if a Republican administration could not actually hamstring the agency on Jan. 21, 2017, those in Congress are continuing to wage a war of attrition. The most recent omnibus funding agreement reduced EPA spending to its lowest level since fiscal 2008 while forcing the agency to employ its smallest workforce since 1989. House Speaker Paul Ryan, R-Wis., boasted the measure “blocks EPA overreach.”