Earlier this month, the Senate voted 83-14 to confirm Gen. George Casey as Army Chief of Staff. Ten of the "no" votes came from Republicans, four of whom—John McCain (R-AZ), John Ensign (R-NV), Saxby Chambliss (R-GA) and Lindsey O. Graham (R-SC)—serve on the Senate Armed Services Committee (SASC) and had grilled Gen. Casey during his confirmation hearing, forcefully taking him to task for lack of progress in Iraq during his tenure as the commander of US ground troops there.

Sen. Carl M. Levin (D-MI), chairman of the Armed Services Committee, who voted in favor of Casey’s confirmation disagreed "It is not fair that General Casey be tagged with failures, massive failures which were caused by the false policies, the wrong policies, the deceptions, the ignorance, the arrogance, the cockiness of civilian leaders in this administration," Levin said.

But Sen. John E. Sununu (R-NH), who is not a member of the SASC, had an answer for Durbin. "There are many factors that contributed to the failure to improve the situation [in Iraq], but ultimately our military leadership has to bear some responsibility for its choices. Simply put, we shouldn’t reward a lack of success on the field of command with such an important promotion."

This is the central issue of civil-military relations during wartime. How much responsibility for victory or defeat does a military commander bear? In the past, it was not unusual for states to execute unsuccessful generals. The Romans did it routinely. In 1757, at the outset of the Seven Years War, the British condemned Admiral John Byng to death for failing to "do his utmost" during the Battle of Minorca.

In his novel Candide, Voltaire satirized the Byng affair. Observing the execution of an officer in Portsmouth, Candide is told "Dans ce pays-ci, il est bon de tuer de temps en temps un amiral pour encourager les autres" ("in this country, it is wise to kill an admiral from time to time to encourage the others"). While the United States has not executed failed commanders in the past, it has certainly relieved or cashiered them.

No one denies that Gen. Casey is a honorable man and a noble soldier. But like one of his predecessors, the late Gen. William Westmoreland, who after his tenure as Commander, U.S. Military Assistance Command, Vietnam (COMUSMACV), was also promoted to Army Chief of Staff, there is a perception that having failed in Iraq, Gen. Casey is now being "kicked upstairs." Is this a true characterization of Casey’s promotion to Army Chief of Staff? If so, what does it say about US military promotions?

Students of the Vietnam War, including many who served in the conflict, traditionally have blamed America’s defeat on President Lyndon Johnson and his secretary of defense, Robert McNamara. But there is an emerging consensus that while they do bear much of the responsibility for the defeat, Gen. Westmoreland is also culpable. During his time as COMUSMACV, he implemented a flawed operational approach to the war.

Many historians often write as if North Vietnam was always destined to win the Vietnam War and the United States was always destined to lose it. In this view, Hanoi pursued a course of action with little regard for what the United States did. But new studies have confirmed that the North Vietnamese strategy was greatly affected by US actions. The lesson here is that countries are not destined to win or lose wars. Victory or defeat depends on decisions actually made and strategies actually implemented. And in Vietnam under Gen. Westmoreland and Iraq under Gen. Casey, the United States pursued flawed strategies.

Westmoreland’s operational strategy emphasized the attrition of the forces of the Peoples’ Army of Vietnam (PAVN) forces in a "war of the big battalions": multi-battalion, and sometimes even multi-division sweeps through remote jungle areas in an effort to fix and destroy the enemy with superior fire power. In so doing, he emphasized the destruction of enemy forces instead of protection of the South Vietnamese population by controlling key areas.

Unfortunately, such "search and destroy" operations were usually unsuccessful, since the enemy could usually avoid battle unless it was advantageous for him to accept it. But they were also costly to the American soldiers who conducted them and the Vietnamese civilians who were in the area. In addition, he ignored the insurgency and pushed the South Vietnamese aside. Nonetheless, Gen. Westmoreland was promoted to Army Chief of Staff.

In contrast, his successor as COMUSMACV, Gen. Creighton Abrams, followed a policy of "one war," integrating all aspects of the struggle against the communists. The result was what Lewis Sorley has called "a better war" in which the United States and South Vietnamese essentially achieved the military and political conditions necessary for South Vietnam’s survival as a viable political entity.

The case against Gen. Casey is that he abandoned an offensive strategy that, with more troops, had the potential to work and assumed a defensive approach that ceded the initiative to the enemy. The key to victory in Iraq was and continues to be the defeat of the Sunni insurgency centered in Anbar province. In late 2004 and continuing well into 2005, the Coalition conducted a campaign—a series of coordinated movements, battles and supporting operations designed to achieve strategic or operational objectives within a military theater—intended to deprive the insurgency of its base in the Sunni Triangle and its "ratlines"—the infiltration routes that run from the Syrian border into the heart of Iraq. The operational concept was "clear and hold."

There were two parts to the operational strategy. On the one hand, no force, conventional or guerrilla, can continue to fight if it is deprived of sanctuary and logistics support. Accordingly, the central goal of the U.S. strategy during this period was to destroy the ratlines following the Euphrates and Tigris Rivers. On the other hand, the key to defeating an insurgency is to provide security to the population. The first element of the strategy met with success. But because of insufficient forces, the second part failed.

This campaign began in November 2004 with the takedown of Fallujah. Wresting Fallujah from the jihadis was critically important: Control of the town had given them the infrastructure—human and physical—necessary to maintain a high tempo of attacks against the Iraqi government and coalition forces, especially in Baghdad.

In and of itself, the loss of Fallujah didn’t cause the insurgency to collapse, but it did deprive the rebels of an indispensable sanctuary. Absent such a sanctuary, large terrorist networks cannot easily survive, being reduced to small, hunted bands.

With Fallujah captured, the Coalition continued a high tempo of offensive operations designed to destroy the insurgent infrastructure west and northwest of Fallujah, and so shut down those ratlines. Although successful in many respects, these operations seemed like the "whack-a-mole" arcade game: towns were cleared of insurgents but because of limited manpower, the towns were not held. Insurgents returned as soon as Coalition forces moved on.

But then the offensive stopped as training the Iraqis took center stage in the Coalition’s Iraq strategy. Of course, a well-trained Iraqi force is critical to ultimate success in Iraq. Indeed, as more Iraqi troops became available in 2005, they were able to hold some of the insurgent strongholds in Anbar Province. But this shift was accompanied by the consolidation of American forces in large "megabases" in an attempt to reduce the American "footprint" and move US troops to the "periphery" of the fight.

But the shift to a defensive posture enabled the insurgents to regain the initiative that had been wrested from them during the al Anbar offensive. One result of the insurgents’ regained initiative was the bombing of the Grand Mosque in Sammarah, which ignited the sectarian violence that now threatens to destroy the possibility of a united Iraq. Unfortunately, the new disposition of American forces made it impossible for them to provide the necessary security to the Iraqi population as sectarian violence exploded in Baghdad and elsewhere.

So there is a case to be made against Gen. Casey’s promotion to Army Chief of Staff. The danger is that in his new position, he will champion the old ways when the Army is in dire need of cultural change: a shift from thinking only in terms of conventional war, at which the Army excels, but which is less likely in the foreseeable future, to adapting doctrine, training, and organization to the requirements of irregular warfare.

This was the case with Gen. Westmoreland, who as Army Chief of Staff made few changes in his service at a time when they were needed. Those changes, the true beginning of Army "transformation," originated with his successor, Gen. Creighton Abrams. Ironically, the only nominee to be Army Chief of Staff since the 1930s, other than Gen. Casey, who drew negative votes during his confirmation, was not Gen. Westmoreland but Gen. Abrams.

Mackubin T. Owens is an adjunct fellow of the Ashbrook Center and a professor of strategy and force planning at the Naval War College in Newport, R.I. He led a Marine infantry platoon in Vietnam in 1968-1969.