IF HOUSE Republicans have had an obsession to rival their hatred of the Affordable Care Act, it has been their determination to find a scandal in the 2012 attack on a U.S. facility in Benghazi, Libya, in which Ambassador J. Christopher Stevens was killed.

Yet this week those same Republicans are putting U.S. embassies across the world at risk with their shutdown of the U.S. government. More broadly, they are endangering national security at a time when the United States remains under threat from al-Qaeda and affiliated groups.

Sen. Dianne Feinstein (D-Calif.), chair of the intelligence committee, said on the floor of the Senate on Tuesday that 72 percent of the civilian intelligence agency workforce has been furloughed.

“This means that, with the exception of a few intelligence agencies that have a significant number of military personnel, the lights are being turned off and the majority of the people who produce our intelligence, analyze that intelligence and provide warning of terrorist attacks or advise policymakers of major national security events will be prevented from doing their jobs,” she said. “We have ambassadors in threatened capitals . . . [who] rely on their intelligence briefers and the tactical intelligence support to their security teams as much as they rely on the Marines who guard front gates. . . . What we are doing now puts American lives at risk.”

Ms. Feinstein is hardly a rabid partisan, but if her party membership causes you to doubt her, consider the judgment of John B. Bellinger III, who served as a senior national security lawyer in the Bush administration from 2001 through 2009. In a post on the Lawfare blog Sunday, Mr. Bellinger warned that shutdown advocates “should be gravely concerned about the risks they are taking with the security of the United States.”

“Do Tea Party Republicans want the leaders of our intelligence and security agencies focused on protecting the nation, or managing the shutdown of their agencies?” he asked. “[I]f there were another attack against the United States or its facilities around the world (such as an Embassy), Tea Party Republicans and the American people would not be able to blame the Executive branch — and call for Benghazi-like investigations — for failing to keep the country safe. Members of Congress who had forced a government shutdown would themselves be blamed.”

Is it fair to blame Republicans? We believe that any solution to the nation’s fiscal challenge will require concessions from Republicans, who will have to acknowledge a need for more revenue, and Democrats, who will have to agree to slow the growth of entitlement programs.

But Republicans haven’t even put such issues on the table this time around. Instead, having essentially won the short-term budget battle — Democrats were resigned to cuts they abhor — House Republicans insisted on shutting the government in a doomed effort to derail the health-care law. Some of them seem ready to let the nation default in the same doomed cause.

It is reckless behavior in a time of war, and it is, above all, Speaker John Boehner and his allies who are at fault.