As we move into the fall, there’s one overriding foreign policy priority for the United States: Find a strategy to deal with a rising China that protects U.S. interests but doesn’t subvert the global economy.

China is the challenge of our time, and the risks of getting it wrong are enormous. Huawei, the Shenzen-based communications powerhouse, argues in a slick new YouTube video that its critics want to create a new Berlin Wall. That’s not true — Huawei and other Chinese tech companies have allegedly been stealing intellectual property for years and are finally being held accountable — but there’s a real danger that the United States will talk itself into a digital cold war that lasts for decades.

We are at a crossroads: At a conference on U.S.-China relations last month at the University of California at San Diego, a Chinese participant offered a blunt prediction about the future: “We think we are heading toward a partial decoupling of our relationship.” Trump administration officials argue that China has been decoupling itself — denying access to Western firms, even as the United States and its allies provided technology, training and market access.

President Trump reiterated on Wednesday that the administration plans to deny Huawei access to U.S. technology. “It’s a national security concern,” Trump told reporters at the White House. “Huawei is a big concern of our military, of our intelligence agencies, and we are not doing business with Huawei.” That leaves a little wiggle room, but not much.

White House officials tell me the Chinese are mistaken if they think the administration is seeking to cripple China technologically. Officials say their goal isn’t a rerun of the anti-Soviet strategy of containment but something more flexible. One administration official says his colleagues sometimes refer to this still-unnamed strategy simply as “the noun.”

The Trump administration’s problem is that it has gutted the national security process that could devise a systematic plan for dealing with China. Instead, policy is highly personalized and shaped by Trump’s erratic decision-making style. “President Trump is our desk officer on China,” says Michael Pillsbury, an informal White House adviser on Asia policy. Strange as it sounds, that’s probably accurate.

This administration’s sharp policy debates on China strategy are exacerbated because there’s no decision-making process to resolve them. On one side are China hawks such as White House trade adviser Peter Navarro; on the other are would-be dealmakers such as Treasury Secretary Steven Mnuchin. In the middle is Secretary of State Mike Pompeo, who seems to have an instinct for where Trump will eventually land.

“On no issue is the lack of a policy process more visible or dramatic than China,” says Kurt Campbell, who oversaw Asia policy during the Obama administration. He contrasts how the presidents of the world’s two superpowers spent the last weeks of summer. Chinese President Xi Jinping met with top party officials at a beach resort and emerged with a new honorific, the “People’s Leader.” Trump spent those weeks in very public and sometimes self-destructive Twitter barrages, at home and abroad.

Trump has a simple four-word summary of his China baseline, notes one administration official: “Xi is my friend.” Personal diplomacy has its uses, but it’s no substitute for clear policy.

Framing a real China strategy should be Job No. 1 for Trump (and his successor in 2021, if Trump is defeated). Pillsbury described the scope of the challenge in the title of his 2016 book, “The Hundred-Year Marathon.” He told me this week: “We need to change the trajectory that we’re on now. That means running faster and slowing them down.” That’s a good formulation, but both goals require disciplined U.S. policy — something in short supply.

Making good decisions about China (and, implicitly, about the future of global technology) requires a sound U.S. policymaking structure. The best idea I’ve heard is a bipartisan bill introduced this year by Sens. Marco Rubio (R-Fla.) and Mark R. Warner (D-Va.), which would create a new “Office of Critical Technologies and Security” to oversee decisions about China and other key countries.

Trump was right to take the China trade and technology problem more seriously than his predecessors. But the time for Twitter diplomacy and deals with “my friend” Xi is over. U.S. moves on this chessboard should be guided by clear planning, not whim.