The magnitude of the Katrina disaster and the subsequent failure of local, state, and federal agencies to react in a timely manner have led some to call for an expansion of the military’s role in domestic affairs, including law enforcement. "The question raised by the Katrina fiasco," writes Daniel Henninger of the Wall Street Journal, "is whether the threat from madmen and nature is now sufficiently huge in its potential horror and unacceptable loss that we should modify existing jurisdictional authority to give the Pentagon functional first-responder status."

The call for expanding the military’s domestic role did not begin with Katrina. Arguing that "the rising tide of drugs being smuggled into the United States… present[ed] a grave threat to all Americans" and that civilian law enforcement was not effectively dealing with this threat, Congress passed the Military Cooperation with Civilian Law Enforcement Agencies Act of 1981." In 1986, existing law was changed in order to permit the military more leeway in fighting the drug war.

In 2002, Air Force General Ralph Eberhart, the first head of Northern Command, the unified command created in the wake of 9/11 and given responsibility for defending the United States, expressed support for changes in existing law that would expand the military’s domestic powers in the war against terrorism. At about the same time, Senator Joe Biden, a member of the Judiciary Committee, endorsed the idea of granting soldiers the power to arrest American civilians. Meanwhile during his first term, President Bush directed the Departments of Justice and Defense to review the Posse Comitatus Act (PCA) of 1878, the law that limits the use of the military in domestic law enforcement.

This trend toward increased involvement of the US military in domestic affairs is at odds with healthy civil-military relations. In addition, officers traditionally have expressed the fear that involving the military in domestic tasks will undermine the war fighting capabilities of their units and cause their "fighting spirit" to decline.

The United States has avoided such extreme manifestations of "bad" civil-military relations as coups and military dictatorship. Nonetheless, some observers have argued that the state of American civil-military relations has deteriorated seriously since the end of the Cold War. They fear that current trends will result in a large, semi-autonomous military so different and estranged from society that it will become unaccountable to those whom it serves.

Those who advance this view worry about the expansion of the military’s influence and are concerned that the result will be a military contemptuous of American society and unresponsive to civilian authorities. They acknowledge that the crisis is not acute. There are no tanks rumbling through the streets. Instead, they claim, it is subtle and subversive—like a lymphoma or termite infestation—destroying silently from within. These problems, the say, manifest themselves as mutual mistrust and misunderstanding, institutional failure, and strategic incapacitation.

For instance, in the 1990s, the Army in particular engaged in "foot-dragging" as a way of resisting involvement in constabulary missions. Critics also charged that Gen. Colin Powell, then chairman of the Joint Chiefs of Staff, was illegitimately invading civilian turf by publicly advancing opinions on foreign policy. In addition, there were many instances of downright hostility on the part of the military toward President Bill Clinton, whose anti-military stance as a young man during the Vietnam War years did not endear him to soldiers. Many interpreted such hostility as just one more indication that the military had become too partisan (Republican) and politicized.

Some observers claimed that the civil-military tensions of the 1990s were a temporary phenomenon, attributable to the perceived anti-military character of the Clinton administration. But it seems clear that these tensions did not disappear with the election and reelection of George W. Bush as president. Indeed, if anything, they have become more strained as a result of clashes between the uniformed services and Defense Secretary Donald Rumsfeld over efforts to "transform" the U.S. military and the planning and conduct of U.S. military operations in Afghanistan and Iraq. Much of the uniformed services’ campaign against Rumsfeld has been conducted by leaks to the press. All of these tensions will be exacerbated if the laws and regulations are changed to increase military participation in domestic affairs. It is likely that the military will be increasingly politicized.

Indeed, one of the main reasons Congress passed the Posse Comitatus Act in 1878 was the fear that the Army was becoming politicized. Before the Civil War, soldiers and Marines were often used to enforce the fugitive slave laws and suppress domestic violence. For instance, the Fugitive Slave Act of 1850 permitted federal marshals to call on the posse comitatus, "the power of the county," to aid in returning a slave to his owner, and since Congress had held in 1807 that the Army could enforce domestic law, the Army was considered to be part of the posse comitatus. Troops were also used to suppress domestic violence between pro- and anti-slavery factions in "Bloody Kansas." Soldiers and Marines participated in the capture of John Brown at Harpers Ferry in 1859. In response to complaints about the Army’s involvement in supporting the Reconstruction governments in the southern states after the Civil War, Congress passed the Posse Comitatus Act (Section 1385, Title 18 U.S.C.). This legislation prohibits the use of the military to aid civil authorities in enforcing the law or suppressing civil disturbances except in cases and under circumstances expressly authorized by the Constitution or Act of Congress.

While the Posse Comitatus Act is usually portrayed as the triumph of the Democratic Party in ending Reconstruction, the Army welcomed the legislation. The use of soldiers as a posse removed them from their own chain of command and placed them in the uncomfortable position of taking orders from local authorities who had an interest in the disputes that provoked the unrest in the first place. As a result, many officers came to believe that the involvement of the Army in domestic policing was corrupting the institution.

Clearly the active force and the National Guard have an important role in domestic disasters such as Katrina. But before we further relax the legal constraints against the use of the US military in domestic affairs, we need to answer two fundamental questions. Do we really want the American public turning to the military for solutions to the country’s problems, with all that means for healthy civil-military relations? And do we really want to saddle the military with a variety of new, non-combat missions, vastly escalating its commitment to formerly ancillary duties?

If we do, we will find that we have involved the military in the political process to an unprecedented and perhaps dangerous degree. These additional assignments will also divert focus and resources from the military’s central mission of combat training and warfighting.

The fact is that the president has all the power he needs to employ the military in domestic affairs if he needs to do so. It is the so-call Insurrection Act (Chapter 15, Title 10, U.S.C.). Although intended as a tool for suppressing rebellion when circumstances "make it impracticable to enforce the laws of the United States in any State or Territory by the ordinary course of judicial proceedings," presidents used this power on five occasions during the 1950s and 60s to counter resistance to desegregation decrees in the South. Reports indicate that President Bush chose not to invoke the Insurrection Act in the case of Katrina because of concerns that such an action would have been viewed as federal bullying of a Southern Democratic governor.

The response to Katrina indicates that procedures at all levels of government must be streamlined. But the maintenance of both healthy civil-military relations and a combat-ready force dictates that we don’t repeal or modify the Posse Comitatus Act or give the president power beyond that of the Insurrection Act. And by no means should we expect the military to go beyond its current mission of supporting civil authorities in the event of domestic emergencies.

Mackubin Thomas Owens is an Adjunct Fellow of the Ashbrook Center and an associate dean of academics and a professor of national-security affairs at the Naval War College in Newport, R.I. He is writing a history of U.S. civil-military relations.