In August 2019, amid an escalating trade war with China, then-US President Donald Trump fired off a series of tweets directing American companies to “immediately start looking for … alternative[s] to China” and shift their manufacturing back to the United States. The demand sent stock markets into a tailspin and alarmed US businesses with exposure to China.

While Trump ultimately softened his stance, the threat underscored a disturbing reality that the world must face now that he is returning to the White House: the president has the power to sever ties with the world’s second-largest economy, and can do so on a whim.

With Trump’s resounding victory over Kamala Harris, the specter of his impulsive, heavy-handed approach to diplomacy looms large. If his past actions are any indication, corporate America might soon be bracing for another round of erratic, high-stakes maneuvers – or worse – against China.

The US Constitution delegates authority over foreign relations to both the president and Congress, a structure designed to temper executive discretion with legislative oversight. But this balance has shifted dramatically in recent decades. Foreign policy is now overwhelmingly concentrated in the executive branch and goes largely unchecked, a trend that political scientists attribute to a rise in partisanship and a decline in congressional expertise. And with both parties favoring a hardline approach toward China, Trump will have even more freedom to lash out at the country.

Meanwhile, “national security” has proven to be remarkably pliable, extending far beyond traditional concerns such as homeland defense and cybersecurity. It now covers everything from cross-border data flows and supply-chain vulnerabilities to protecting industries deemed too critical to be dominated by foreign competitors.

This broadened definition has enabled presidential actions that would have been unimaginable only a decade ago. Consider some of the measures taken by Trump and his successor, Joe Biden: sanctioning Huawei and ZTE; banning TikTok; blocking Chinese investment in a dating app; launching the controversial “China Initiative” that disproportionately targeted Chinese scientists working in the US; imposing a semiconductor embargo on China; restricting US investment in Chinese artificial intelligence and quantum computers; and, most recently, slapping 100% tariffs on Chinese electric vehicles and batteries.

Many of these aggressive policies should be implemented only in emergencies. But what constitutes an “emergency” has also expanded considerably and now includes curbing China’s rise. And when Trump takes office in 2025, the executive branch’s capacity and willingness to declare an “emergency” and impose extraordinary measures under the banner of “national security” could increase substantially.

While US courts have the authority to check presidential powers – as they did in blocking Trump’s attempts to ban TikTok and WeChat – they have limited oversight of foreign policy. On matters of national security, in particular, federal courts have historically been very deferential – even more so when Congress and the president are aligned. The recent passage of the TikTok legislation illustrates how Congress can quickly restore executive power after a judicial ruling constrains it. As a result, TikTok and other Chinese companies are constantly contending with renewed hostility from the executive, like an endless game of whac-a-mole.

Ironically, this concentration of power in the US presidency mirrors the Chinese governance model that American leaders criticize so sharply. As I show in my book, High Wire: How China Regulates Big Tech and Governs Its Economy, the consolidation of political power in China over the past decade has often led to dramatic policy swings that undermine investor confidence and dampen entrepreneurship. The Chinese government’s recent missteps – from mismanaging the COVID-19 pandemic to crackdowns on the tech and property sectors and now a sluggish response to mounting deflation risks – should serve as a cautionary tale.

The US is likewise beginning to feel the unintended consequences of its own hostile approach toward China. The China Initiative has led to an exodus of talented Chinese scientists, many of whom have returned home. Meanwhile, the effectiveness of tough US sanctions and export controls is waning. Huawei, which initially struggled under these measures, has grown stronger of late, invigorated by state support and a firm resolve to achieve self-sufficiency. In its efforts to contain China, the US risks creating a more resilient rival – one strengthened by the very pressures meant to suppress it.

But instead of reassessing the efficacy of its hardline tactics, US agencies are doubling down on sanctions and restrictions. Even the notorious China Initiative, despite being “discontinued,” persists in a barely concealed form.

So far, much of the discussion about the Sino-American rivalry has framed China’s rise as the primary catalyst for US policy shifts. But this misses a crucial point: the conflict can also be traced back to a democratic deficit in American foreign policymaking. If the US takes increasingly extreme measures to contain China, as it likely will during Trump’s second administration, it risks widening that deficit – and becoming defined by what it opposes.

Angela Huyue Zhang, professor of law at the University of Southern California, is the author of "High Wire: How China Regulates Big Tech and Governs Its Economy" (Oxford University Press, 2024) and "Chinese Antitrust Exceptionalism: How the Rise of China Challenges Global Regulation" (Oxford University Press, 2021).

©Project Syndicate