Trump is breaking an axiom of war. Did no one warn him?

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Opinion by Matthew Lynn

Matthew Lynn is a financial columnist and author. He writes for the Daily Telegraph and the Spectator in London.

The exact origin of the maxim “Don’t fight on two fronts” is lost to time. It can be variously traced back to “The Art of War,” the classic 5th-century B.C. Chinese treatise by Sun Tzu, to Napoleon Bonaparte, or to Field Marshal Bernard Law Montgomery, the main commander of British forces during World War II.

One point is certain, however. No one got around to sharing it with President Donald Trump. The United States has now embarked on two wars at the same time: a trade war with China and Europe, and a real war with Iran. This will surely prove to be a serious mistake.

Trump has an undiminished appetite for conflict. Less than a year ago, on what he oddly called “Liberation Day,” he ripped up the global trading system and imposed punitive tariffs on U.S. trading partners and allies. Earlier this year, he launched a raid to arrest Venezuelan President Nicolás Maduro, and last month, he launched an all-out assault on Iran, aimed at taking out its armed forces and removing its leadership.

An administration that many argued would be isolationist and that promised to put America first has turned out to spend most of its energy trying to reshape the rest of the world.

In fairness, you can make a respectable case for either war. The supposedly rules-based global trading system did at times appear to have turned into a mechanism for transferring wealth and jobs from American workers to other countries. Given persistent U.S. deficits, and with American exporters facing steep tariffs in many countries while U.S. markets remained open, you could certainly argue that the system needed rebalancing. After a decade or two of talking with no discernible change, a more muscular approach has its merits.

Likewise, you can make a perfectly respectable case for removing the regime in Tehran, or at least significantly degrading its military strength. For the better part of five decades, it has been a threat to its neighbors and a persistent sponsor of global terrorism, while brutally suppressing its people and attempting to acquire nuclear weapons. The world would definitely be better off if it fell. There is a strategic rationale to launching an attack even if the risks are huge.

But both wars at once?

There are two big problems. First, alliances get stretched very close to the breaking point. It might be helpful in the Gulf, for example, to be able to call upon French naval forces, or British air support, or Canadian or German defense manufacturing to keep the weapons flowing. But that is very hard to do when you have just slapped punitive tariffs on those countries, impeded their exports and dismissed their leaders as irrelevant. To put it mildly, goodwill is in short supply.

The issue is not that anyone in Europe — apart from a few extremists — has any sympathy with the regime in Tehran. It is that European voters understandably have little sympathy with a president who has been attacking their exporters and demanding that jobs be transferred across the Atlantic.

Next, very quickly the objectives start to clash. It is difficult to maintain all the levies and restrictions on imports demanded by the trade war when supply chains are being thrown into chaos by the closure of shipping lanes in the Gulf, when the price of oil is exploding and when critical minerals and components are needed to fight the war.

Even worse, it was always going to be hard to maintain political support for tariffs if they led to a spike in inflation — even if you believed that was a short-term price worth paying to restore manufacturing capacity. But why throw fuel on that particular fire with a military action in the Middle East? (“Wait, war in the Gulf drives energy costs higher? Why did nobody tell us?”)

If inflation goes much higher, the president may well end up lowering tariffs to contain it, effectively surrendering ground in the trade war. Alternatively, he may decide to end the attack on Iran before the task has really been finished, simply to prevent prices from rising and losing the trade war. Either way, he will have to decide which war is the priority.

It would have been far better to fight Iran first, get that wrapped up, and then launch the trade war. Or else contain Iran until the global trading system had been rebalanced and America’s main allies were feeling less aggrieved.

Either way, the White House could have stayed 100 percent focused on a single goal. Instead, it has attempted to achieve two huge objectives at the same time. The result is already becoming painfully clear. The real war makes the trade war harder to win, and vice versa.

As Sun Tzu, Napoleon or Montgomery — or countless other military strategists — would point out to Trump, attempting to fight on two fronts just means you end up losing everything.