Some time ago one of my readers asked that I write about how the rules of engagement (ROE) severely restricted US forces freedom of action and thus played a significant role in the resultant “loss” in Vietnam.  In this case ROE were linked to limited war. What is limited war you ask?

Limited war is where one side in a conflict decides to limit its application of military force for a whole series of reasons.  The Vietnam War really had two phases:

1. The pre-1 April 1968 phase where the US was fighting to win though with significant limits on the application of force, and
2. The post 1 April 1968 date where the goal was to achieve a negotiated agreement. Initially this phase had even more restricted ROE, but after Nixon’s perception of North Vietnamese intransigence there was a significant loosening of the ROE—decreasing the limits on the use of military force.

The above raises several questions:

• What were the initial limits and why were they imposed?
• What is so significant about 31 March 1968? What were the limits in the ROE?
• What were Nixon’s relaxation of limits?

When the US began its escalation of the use of force in Vietnam in 1964/5 there were significant limits placed upon the forces.  Cambodia and Laos were off limits to conventional forces, as was North Vietnam.  The bombing of North Vietnam was severely limited as to the targets that could be engaged.  The whole theory of limited war was meeting a test.  A test that it failed, but more about that later.

These limits were imposed on US forces because of a fear that any expansion of the war would cause the Chinese to intervene. The memory of Korea was still keen in strategists’ minds.  There was also fear of a confrontation with the Soviet Union.  For these reasons there were severe limits placed upon US forces.

In late 1967 the North Vietnamese tested these limits with the extreme shelling and limited attacks across the DMZ in the vicinity of Cam Lo.   Unbeknownst to the Americans this was a test—a test to see if it would abide by its limits and not invade North Vietnam.  When the US did not invade the North Vietnamese were free to move several divisions west to come down the Ho Chi Minh trail and attack Khe Sanh.  Which they did.

What is so significant about 31 March 1968?  The evening of 31 March President Johnson announced his partial bombing halt as a means to entice the North Vietnamese into negotiations to end the war.  It was at this point that the war was “lost.”  As recounted elsewhere (Expendable Warriors) a proposed offensive military action into Laos was deemed to be politically unacceptable.  The war had been won on the ground in Vietnam but lost politically.  The US was unwilling to lift its limits and win the war on the ground and North was not fighting with any limits.  Instead increased limits were imposed on US forces.

North Vietnamese intransigence and an attempt to disengage US forces while not increasing the degree of loss lead to the Nixon Administration strategy of Vietnamization.  This was coupled with several expansions of the war—relaxation of the limits imposed on US forces.  First was the invasion of Cambodia as an attempt to destroy North Vietnamese Army (NVA) sanctuaries and to buy time for Vietnamization to take hold.

The second expansion was Lam Son 719A—the invasion of Laos in 1971 to cut the Ho Chi Minh trail.  For several reasons this Vietnamese attack with US support was a miserable failure.  The main reason probably being the loss of surprise—the NVA were waiting and the Army of the Republic of Vietnam (ARVN) got mauled.

The final escalation was the use of B-52s over Hanoi and Haiphong.  Previous bombing restraints/limits were relaxed and a massive bombing finally caused the North Vietnamese to agree to a settlement.  In hiding the overall loss Nixon/Kissinger called it “Peace with Honor”.  The POWs came home.  T

In Vietnam we relearned the lessons of Korea.   When one side is fighting a limited war—limited in ways and means and the other side is fighting an unlimited war—applying all of the ways and means at its disposable to win the outcome is a t best a draw.  Does or should the MacArthur dictum: “there is no substitute for victory” apply?  In the Gulf War we saw the limits replaced by the Powell Doctrine of “Over-whelming Force.”  However there were limits in that conflict such that several years the second Bush administration felt that it had to fight another war against Iraq—in short to do what the first Gulf War had prevented –the over throw of Saddam Hussein.

To return to the original issue of ROEs and limited war it should be clear that at no time except a nuclear threat will the United States not fight a “limited war.”  But the extent of those limitations will clearly have a potential impact on the outcome of the conflict.  Politicians and military strategists must decide before the conflict begins as to whether any limits being considered will prevent the achievement of the military objectives that have flowed from the political objectives of a conflict.