While Tea Partiers like Sharron Angle in Nevada and Rand Paul in Kentucky are challenging Washington's politics-as-usual on the campaign trail, Greg Abbot, Mike Cox and Ken Cuccinelli are opening a crucially important second front against the federal Leviathan in the courts.

Abbot has filed two suits in six weeks against the U.S. Environmental Protection Agency in defense of an innovative Texas anti-emissions program for certain older industrial operations. Federal law caps emissions by source within such 122 covered facilities in Texas.

The Lone Star State's 16-year-old program allows variances among individual sources within a plant as long as it stays under the overall cap. Texas officials claim their permitting cut ozone and nitrogen oxide emissions 22 percent and 46 percent reduction, respectively, which is considerably more than the 8 percent and 27 percent reductions achieved nationally.

But EPA now claims the Texas program violates the Clean Air Act even though Section 101 of that law says air pollution prevention "is the primary responsibility of the States and local governments." Section 110 further says each state "shall have the primary responsibility for assuring air quality within the entire geographic area comprising such State."

So, Abbott is challenging EPA in federal appeals court "to defend the State's legal rights and challenge improper overreach by the federal government."

In Michigan, Attorney General Cox is vigorously supporting Arizona's controversial immigration law, joining eight other states in filing an amicus brief in federal court against the Justice Department's attempt to have it declared unconstitutional.

"President Obama is using taxpayer dollars to stop a state's efforts to protect its own borders," Cox said. "The federal government's attempt to stop Arizona's law flies in the face of congressional intent, and should be swiftly denied by the Court."

Cox is in a close race with Rep. Pete Hoekstra for the GOP nomination for governor. The primary will be decided Aug. 3. Cox also is among the state AGs who have filed suit against Obamacare.

Which brings us to Virginia's Cuccinelli, who was first to file suit against Obamacare's provision forcing every individual American to purchase a federally approved health insurance program.

"If the government prevails and Congress may use the Commerce Clause to order Americans to buy private health insurance, then Congress will have been granted a virtually unlimited power to order you to buy anything. That would amount to the end of federalism and our more than 220 years of constitutional government," Cuccinelli said.

The common theme among these three state leaders is their aggressive willingness to challenge what they see as Washington exceeding its constitutional bounds and trampling state prerogatives in the process.

Abbott, Cox and Cuccinelli are leaders in a growing movement among state officials to stop meekly asking "how high" every time federal bureaucrats order them to jump. They take seriously the 10th Amendment's command that "the powers not delegated to the United States by the Constitution, nor prohibited by it to the States, are reserved to the States respectively, or to the people."

Depending on the issue, anywhere from a dozen to as many as half of the states are involved in such challenges now. With conservative Republicans almost certain to gain more AG jobs in November, odds are good that there will be many more 10th Amendment suits in the years ahead.

And that will be a very good thing. Since the states created the federal government, not the other way around, the 10th Amendment is at the heart of the U.S. Constitution. Detecting a pulse, however, has been all but impossible for too many years.

State leaders like Abbott, Cox, and Cuccinelli are applying the defibrillator to the heartbeat of America.

Mark Tapscott is editorial page editor of The Washington Examiner and proprietor of Tapscott's Copy Desk blog on washingtonexaminer.com.