The breadth and complexity of President Barack Obama’s plans to regulate greenhouse gases from power plants are probably a nightmare to some of the many Hill staffers, reporters and interest groups following the issue, but it may be a dream come true for civics teachers.

That’s because the twin regulations — one governing new facilities and the second targeting emissions from existing plants — have sparked an unusual frenzy of government activity nationwide, both at the state and federal levels.

According to the National Conference of State Legislatures, at least 72 bills or resolutions related to the Environmental Protection Agency’s plans have surfaced in 27 states, spanning Alaska to Virginia, with 10 of the measures already enacted into law.

At the federal level, all three branches of government are actively involved in the debate over the plan — a level of engagement all the more noteworthy considering the EPA hasn’t yet finalized the regulations.

As agency staff labor to put the finishing touches on the rules to meet the self- appointed summer deadline, Congress is working just as diligently to thwart what Republicans say is a legally dubious executive overreach.

“I will not stand by and let the EPA force states to spend their resources in a manner that will harm local economies and force their citizens to pay for the president’s misguided legacy,” Senate Environment and Public Works Chairman James M. Inhofe, R-Okla., said recently at a hearing on the issue. “Especially when it is not a matter of if the Clean Power Plan will be ruled illegal, but when.”

Critics of the plan are so confident it will be thrown out that a dozen states took the unusual step of asking a federal appeals court to block the EPA from finalizing the proposal for existing plants. While a three-judge panel of the U.S. Court of Appeals for the District of Columbia Circuit expressed doubts about the ripeness of the case during oral arguments last month, the lawsuit offers a preview of what’s to come after the rules are finalized.

New litigation challenging both rules is expected to be filed as soon as they are issued, and more suits will follow as lawyers sort through the fine print.

Despite majorities in the House and Senate, simple arithmetic hampers Republicans’ efforts to block the rules through legislation. There’s several paths to doing so through Congress, but mustering the requisite two-thirds majorities needed to override Obama’s veto pen is seen as a heavy lift.

Nonetheless, Senate Majority Leader Mitch McConnell, R-Ky., has proven adept at reinserting Congress in the debate. In March, the coal-state senator publicly urged states to defy the EPA by refusing to submit plans for complying with the rule for existing plants, which he argued will eventually be thrown out by a court.

It’s a risky proposition for the states, which face the prospect of the EPA stepping in and mandating its own compliance plan in their borders. Oklahoma Attorney General E. Scott Pruitt last week likened the threat of an EPA backup plan to “the proverbial gun to the head” in an appearance before Inhofe’s committee.

However, Oklahoma Republican Gov. Mary Fallin last month became the first governor to take McConnell’s advice, issuing an executive order prohibiting the state from submitting a compliance plan to the EPA.

McConnell also surprised climate advocates by publicly warning foreign nations against negotiating with the Obama administration on an international climate agreement that is supposed to be completed in Paris later this year.

When EPA Administrator Gina McCarthy showed up at the Senate Appropriations Committee earlier this month to defend the agency’s fiscal 2016 budget request, McConnell reminded her Congress couldn’t pass a cap-and-trade climate bill even when Democrats controlled both chambers.

“The failure of Congress to sign off should signal to other countries that they should proceed with caution in the December climate talks in Paris,” he said.

During the hearing, McConnell also suggested a new avenue for critics when he read aloud from an obscure section of the Clean Air Act he said would require states to gain congressional approval to form regional compacts for complying with the rule for existing plants.

David Doniger, a longtime attorney with the Natural Resources Defense Council who helped develop the group’s suggestions for how the EPA could regulate greenhouse gases from power plants, later dismissed McConnell’s reasoning as a non-issue. Still, the majority leader’s point highlights that the EPA critics will leave no stone unturned in their quest to void the regulations.

Responding to McConnell, McCarthy reiterated the EPA is acting under the authority provided by Congress, and predicted the rule will “withstand the test of time in the courts.”

“Yeah, that’s going to be the test,” McConnell responded. “You’re going to have to prove it in court.”

Ed Felker and Lauren Gardner contributed to this report.