The world is complicated. Who knew?

By his own admission, not our president. Donald Trump’s steep on-the-job learning curve is taking place as the tectonic plates of global politics threaten to collide.

The troubles are many: North Korea’s missile tests, Russia’s belligerence, Syria’s civil war, Middle East unrest, the European Union and its stabilizing principles on the ropes, fighting in Afghanistan, a possibly tainted election in Turkey that paves the way for a dictator.

Managing this would be hard even for experienced hands. Trump’s challenge is compounded by a foreign policy devoid of core principles, the marginalization of the State Department, a tendency toward impulsiveness, and Trump’s personal conflicts of interest.

A Syrian air base was bombed after Trump saw photos of child victims of a chemical attack, a reversal of the nonintervention strategy on which he campaigned. Trump congratulated Turkish President Recep Tayyip Erdogan after an election that made Erdogan more of an authoritarian strongman — despite alleged voting irregularities and international condemnation, despite the State Department’s response emphasizing support for the democratic development of Turkey, and, perhaps, because of Trump’s considerable business interests in that country.

Spiking the collective nervousness was Tuesday’s news about the U.S. aircraft carrier and strike force — Trump called it “an armada” — that supposedly were steaming toward North Korea to send a powerful signal of deterrence. In fact, they were headed in the other direction, to the Indian Ocean, 3,500 miles away. It took days to get them turned around; they’re not scheduled to arrive in the region until next week. Whether the result of bad communication or sheer incompetence, the incident was a metaphor for a president relying on instincts, not knowledge.

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Trump said he learned in his recent meeting with Chinese President Xi Jinping how complicated North Korea is. That’s alarming. To get China to exercise its influence, Trump said it is not a currency manipulator, walking back another major campaign declaration. And what did the United States get out of it? On the night Trump dined with Xi at Mar-a-Lago, China awarded monopoly rights to the first daughter’s company to market three new trademarks for Ivanka Trump brand jewelry, bags and spa services in China. Family business or the business of the nation?

The emerging picture is of a foreign policy neophyte playing one hand at a time, while Chinese and Russian adversaries play the long game. There is no logical coherence to Trump’s actions, no philosophy to guide them. He says he doesn’t want to be predictable, good strategy in crafting a business deal but disquieting to allies who don’t know whether they can depend on you. Experts say North Korean dictator Kim Jong Un is unpredictable, has no track record and is either crazy or crazy like a fox; the same can be said of Trump. And Kim is not the only one testing him. On Monday, U.S. fighter jets intercepted two Russian bombers just off the coast of Alaska.

The consequences of a rash decision now go far beyond losing a few billion dollars or making a sour deal. An unstable world needs more steady leadership, not less, from the United States. — The editorial board