Proportionate responses to threats do not work

For one of the few times in his presidency, Donald Trump drew bipartisan support for his last-minute decision not to retaliate against Iran for shooting down a $220 million Navy Global Hawk drone last week.

The president said that the likelihood of some 150 Iranians being killed in a counter-attack was not a "proportionate" response for destroying an unmanned drone. His top advisers recommended otherwise. Immediately the question of whether this decision will be perceived as a sign of prudence or weakness by friends and rivals reverberated around the blogosphere.

Since World War II, most American presidents have succumbed to the doctrine of proportionality. Korea was fought as a "police action," not a war, even though 34,000 Americans died fighting the North Koreans and Communist Chinese. Vietnam demonstrated the folly of proportionate response, then called controlled escalation, because Hanoi could easily out-escalate Washington, understanding that the war was not being fought in rice paddies and jungles but in American living rooms. Some 58,000 Americans and countless Vietnamese lost their lives in that pointless war.

During the Cold War, a surprising number of U.S. aircraft were shot down by the USSR. In January 1968, the USS Pueblo was seized by North Korea in international waters some 25 miles off the Korean coast. Aside from sailing two aircraft carriers off Korean waters and because of the Tet Offensive and the Vietnam War, Washington had little appetite or capability to engage in a second war to retrieve Pueblo.

The Reagan administration produced the Weinberger-Powell Doctrine. Caspar Weinberger was secretary of defense from 1981 to 1987 and argued that the United States would intervene with force only under certain conditions. When it did, it would do so "overwhelmingly." Gen. Colin Powell, chairman of the joint chiefs of staff from 1989 to 1993, modified this doctrine to one of "decisive force" and applied it in the 1991 Iraq War that eviscerated Saddam Hussein's army, driving it from Kuwait in the "100-hour campaign."

In other American uses of force since, avoiding collateral damage and harming non-combatants became proportionate priorities. The 78-day NATO bombing campaign of Serbia in 1999 to stop the slaughter of Kosovo Muslims reflected this constraint. Aside from bombing the Chinese embassy in Belgrade, this aerial campaign did little damage to Serbian forces and only after the use of ground forces became an option did President Slobodan Milosevic accede to the pressure.

The Afghanistan 2001 intervention, followed by the second Iraq War of 2003 may not have been seen as proportionate responses to September 11th. But both were. Relatively modest military force was needed in quickly routing the Taliban and overwhelming the Iraqi Army the second time with few American casualties initially. But the failure to plan for what next turned that military success into a catastrophe.

Similarly pursuing the ill-named "war on terror" antiseptically with precision airstrikes from manned and unmanned platforms was proportionate in the sense collateral damage was to be minimized. The tragic miscalculation was that for every death, unintended or otherwise, many would volunteer as replacements. What should have been learned from Vietnam, namely, killing one's way to victory was a fool's errand, had been ignored or forgotten by both Republican and Democratic administrations.

Today, with the downing of the Global Hawk unmanned vehicle, the White House must understand that a proportionate response will not work in dealing with Iran. The catastrophic error made by the Trump administration was withdrawing from the Joint Comprehensive Plan of Action. If followed, and Iran remained in compliance, that agreement would have prevented Iran from ever developing a nuclear weapon. The administration will never get a better agreement as Iran will not retrench from its reliance on missiles and proxies to further its security. However, few in senior U.S. government positions believe that.

The United States is stuck. Its principal allies in the region -- Saudi Arabia, the United Arab Emirates and Israel -- view Iran as THE threat. The other signatories to the JCPOA strongly opposed the American withdrawal. The ayatollahs will not submit to a campaign of maximum pressure that challenges their authority. Given the presidential tactic to threaten and bully first with "fire and fury," and then capitulate (North Korea and Mexico) or ignore (Venezuela), his choice for Iran is simple.

Only diplomatic actions to defuse these tensions and ultimately end sanctions in return for an updated JCPOA will work. In essence, such a deal will be largely identical to the one negotiated by the Obama team but one in which Trump can declare victory. But, as in Vietnam, the fatal flaw in proportionate responses and gradual escalation is that the other side will escalate more effectively than we can.

Harlan Ullman is UPI's Arnaud de Borchgrave Distinguished Columnist. His latest book is "Anatomy of Failure: Why America Has Lost Every War It Starts." Follow him @harlankullman.