Unless Congress acts, this summer the Pentagon will begin making across-the-board cuts in defense programs — cuts that will eventually be so deep that the chairman of the Joint Chiefs of Staff has said they will end the United States’s status as a global superpower. Yet there seems to be almost no sense of urgency among congressional Republicans for immediate action to stop this gutting of the country’s national defense. Ronald Reagan, the architect of “peace through strength,” would be appalled.

The GOP shares a large part of the blame for putting our military in this predicament. As part of last year’s Budget Control Act, Republicans agreed to $600 billion in automatic defense cuts (scheduled to begin in January 2013) if the congressional deficit-reduction supercommittee failed to reach agreement. The GOP refused to include automatic tax increases as part of this sequester. But automatic cuts to national defense? This Republicans were willing to risk.

Now we are facing the consequences. On Wednesday, Adm. Jonathan Greenert, the chief of naval operations, said in testimony before the Senate Appropriations Defense subcommittee that implementing these automatic cuts will cause the equivalent of a government shutdown for the Pentagon next year. U.S. military operations, he said, will essentially grind to a halt while the Defense Department diverts its resources to implementing the mandated cost-cutting measures. As for the economic impact, a study by the Aerospace Industry Association found that cuts on the scale of sequestration will result in the loss of more than 1 million jobs. Defense Secretary Leon Panetta has put the costs even higher: 1.5 million jobs lost and a 1 percent hike to unemployment.

Most Republicans see this as a problem that can be put off until January 2013, either in a lame-duck congressional session or when (they hope) a new Republican president takes office. They are dangerously mistaken. Chairman Martin Dempsey has told the Senate Budget Committee that defense contractors are already making decisions to lay off workers in anticipation of sequestration. And to meet the January deadline, the Pentagon will have to begin canceling programs this summer. Many of these decisions, once made, could prove irreversible. A shipyard or aircraft production facility closed because of program cancellations will not be there when we are ready to buy ships and planes again.

Leading the charge to save the armed forces from this debacle is Arizona Sen. Jon Kyl, the second-ranking Republican in the Senate. He has introduced legislation to replace $110 billion in combined defense and nondefense cuts in the first year of sequestration with reductions in other federal spending. In the House, Armed Services Committee Chairman Buck McKeon (R-Calif.) is leading a similar effort.

Why would the Democrats help the GOP reverse sequestration? After all, it turns out they out-negotiated the GOP in designing the sequester — putting defense on the chopping block while exempting many of their most cherished programs from automatic cuts. But Democrats still have some skin in the game. The National Education Association has complained that sequestration will hit nearly every Education Department program — including School Improvement Grants that help failing schools ($41.7 million in cuts) and Head Start preschool programs for poor families (which would be cut by $589.7 million).

The Kyl and McKeon bills pay for reversing the first year of the sequester through federal employee attrition and by extending President Obama’s federal pay freeze through 2014. But both men are open to alternatives. Kyl says he has organized a task force this week “to identify any possible combination of savings, whether discretionary or mandatory, and even sources of revenue if that’s what it’s going to take to get a bipartisan coalition to get this done.” He points out that Democrats and Republicans agreed in principal on some $1 trillion in spending cuts in the supercommittee, and that Republicans put some $300 billion in new revenue on the table, (though many of those were used to pay for the payroll tax extension). “You’ve got a lot of low-hanging fruit” in the first year, Kyl says. “The really discouraging thing is that if it’s this hard to do for the first year … how hard is it going to be in the fourth and fifth and sixth year?”

An additional problem: President Obama has threatened to “veto any effort to get rid of those automatic spending cuts” absent a grand bargain that includes massive tax increases. Kyl says, “When his own defense secretary says that [sequestration] would be catastrophic, it seems to me that the president needs to readjust his thinking on that.”

Obama does need to readjust his thinking, but so do Republicans. Says Kyl, “I’m worried that there’s a lack of urgency [in our party]. I’m worried that there’s a lack of appreciation of the consequences and that people who just got elected are more concerned about the green eyeshade approach to things than they are national security.”

Iran is pursuing nuclear weapons. China is dramatically increasing its defense budget. The Middle East is in turmoil. Terrorists are plotting attacks. Gen. Dempsey recently told Congress, “We are living in the most dangerous time in my lifetime.” Republicans who proudly call themselves “constitutional conservatives” need to remember their first responsibility under the Constitution is to “provide for the common defense.” If they don’t reverse the sequester, they will have failed that responsibility.