(Reuters)

“It’s all under control: Mattis is in charge.” That, or words to that effect, is what U.S. national security officials have been telling European allies in recent days. Don’t worry. There won’t be any surprises. The defense secretary is making all the big decisions.

A similar message is being repeated in Washington. This month, Jim Mattis told a Senate panel that the president had given him the authority to make all of the ground-level military decisions in Afghanistan, including decisions about troop deployment: “I will set the U.S. military commitment,” he said. No one was surprised. It’s now common knowledge that the president does not read complex security briefings, so the decision to hand off to his top commander has a certain logic.

To many, this solution is appealing. Certainly some of the Europeans who have heard this form of reassurance feel better, and probably a lot of Americans do, too. After all, the world is dangerous. A U.S. strike plane shot down a Syrian government fighter jet this week and the Syrian government has promised to retaliate. Tensions are high on the Korean Peninsula. The war in Afghanistan isn’t over.

With so many crises on the horizon, it seems like a good time to leave competent military experts in charge. Except that it isn’t — because it never is.

On the contrary, “Mattis in charge” is a formula for disaster, but not because Mattis is flawed or experts are bad. Mattis is a remarkable public servant, and experts are fundamental to good government. There should be more of them. Their input should be valued and respected. The Trump administration’s failure to use them, especially in foreign policy, will someday be remembered as one of its most catastrophic failures.

But a U.S. foreign policy run by military technocrats will have the same deep flaws as the governments run by economic technocrats that are sometimes installed in countries engulfed by economic crisis. A foreign policy, like an economic policy, can succeed only if it has political backing. Difficult decisions will be accepted by the public only if they have political legitimacy. Military decisions in particular should be part of a carefully thought-out strategy, one that has been cleared by Congress, debated in public and discussed not only in the Pentagon but also in the State Department and the other institutions, staffed by experts, that we have created for this purpose.

It’s appealing, of course, to let the Pentagon make decisions about troop levels in Afghanistan. The Pentagon has a better understanding of that war than the White House, especially this White House. But decisions about troop levels are tactical, not strategic. If we decide to send more soldiers to Kabul, who will take on the task of explaining the larger purpose of that war? Who will tell the American people how it is serving long-term U.S. interests? If soldiers die in Afghanistan, who will explain to their families why their sacrifice was justified? Those aren’t tasks for the defense secretary, however competent. Those are tasks for elected officials, men and women who have been chosen by a democratic political process exactly for that purpose.

A military policy run solely by the Pentagon creates confusion, too. U.S. allies may be relieved to hear the Pentagon’s quiet offers to protect them. But if America’s allies are listening to Mattis, America’s enemies are watching the White House, and they will make decisions based on the president’s behavior, not that of his defense chief. Russia will have noticed Trump’s chilly treatment of Europe and his attacks on Sweden and Germany. North Korea will have heard his demands for more money from South Korea. The gap between the Pentagon’s worldview and that of the White House is so wide that it is actually dangerous: It may lull allies into complacency, while luring enemies into adventurism.

It’s far from clear, in any case, that the Pentagon has all the answers. Military authority is one of the few forms of authority that we all still respect, and the patriotism and dedication of decorated generals cannot be questioned. But do we want them running the United States’ relationships with the rest of the world? Step back for a minute and ask yourself how many American foreign policy successes can be attributed to the U.S. military in recent years — and count how many foreign policy failures were its fault. The peaceful end of the Cold War, the reconstruction and reintegration of ex-communist Europe — these were largely the work of diplomats, politicians and civil society working together. The disastrous occupation of Iraq — this was the work of the Defense Department, which deliberately cut out the State Department.

Once again, I respect Mattis and am glad that he’s there. But let’s not pretend that his leadership can substitute for the void in the White House, the absence of strategy, tactics and rational thought in the foreign policy apparatus in the Trump administration.

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