America’s friends and foes brace for a new world under Trump

Trump, whose Republican party also regained control of the Senate, has pledged to increase import tariffs and cut support for allies that don’t spend adequately on defense. He has also said he would work for a rapid end to Russia’s war in Ukraine.

Global heads of state and government congratulated Trump on his win, which could jolt both U.S. friends and foes.

For China, Trump’s return promises to ignite a new phase in a trade war that began during his first term of office at a time when broader relations between Washington and Beijing are strained.

Trump on the campaign trail floated plans to impose tariffs of 60% on all Chinese imports, a significant increase from the more modest tariff increases on some Chinese goods that were a signature policy of his first term as president.

In the Middle East, a second Trump administration is likely to go back to a “maximum pressure" policy on Tehran, as it did during Trump’s first term, according to people briefed on thinking within Trump’s circles.

That could reshape dynamics in a region where Iran and its proxies are engaged in a multi-front conflict with Israel. Israeli Prime Minister Benjamin Netanyahu, a Trump supporter who quickly congratulated him, could push back harder against Iran.

For Ukraine, where Russian troops control almost 20% of the country, a Trump presidency increases uncertainty about Kyiv’s continued ability to fend off Moscow’s invading forces without the enormous financial and material support the U.S. has provided.

President Volodymyr Zelensky congratulated Trump on “his impressive election victory" and lauded Trump’s “commitment to ‘peace through strength.’" But the two have had at-times fraught relations, and prominent Trump backers have expressed wariness about U.S. support for Ukraine.

Many Ukrainians are concerned that Trump may weaken Kyiv’s hand by cutting critical military and financial support or seeking a deal with Russian President Vladimir Putin that could cede territory and influence to Moscow. Putin has repeatedly said he is only interested in a peace deal that would disarm Ukraine and prevent it from joining NATO.

At North Atlantic Treaty Organization headquarters in Brussels, officials now face questions about the U.S.-led organization’s future. Trump has repeatedly spoken harshly of the military alliance because most European members have long lagged behind the U.S. on military spending.

European outlays have reversed over recent years, rising sharply after Russia’s invasion of Ukraine. Whether the increase, which began during Trump’s first administration—soon after Moscow began hostilities toward Kyiv—will be sufficient to placate a new Trump team remains an unknown that has alliance diplomats on edge.

NATO’s new Secretary-General Mark Rutte, who as Dutch prime minister pushed against Trump in 2018, has recently been talking up the alliance’s need to spend and do more. On Wednesday morning he quickly congratulated Trump.

“I look forward to working with him again to advance peace through strength through NATO," Rutte said. “Through NATO, the U.S. has 31 friends and Allies who help to advance U.S. interests, multiply American power and keep Americans safe.

But further increases in military spending will require action by governments and legislatures among the alliance’s 32 members—29 of which are European—so fast action is difficult.

Nearby in Brussels, European Union officials have plans to respond to pressure from Trump, who during the election campaign repeatedly voiced anger with the U.S. trade deficit with the EU in physical goods.

EU officials and diplomats emphasized in recent weeks that they don’t want a trade war. But they said Europe would be ready to respond with targeted countermeasures if the next U.S. administration moves ahead with heavy tariffs.

“Millions of jobs and billions in trade and investment on each side of the Atlantic depend on the dynamism and stability of our economic relationship," said European Commission President Ursula von der Leyen.

Decisions on which American goods might be targeted for retaliation would depend on the details of any U.S. trade measures, as well as which U.S. states and electoral districts are viewed as the most politically sensitive.

Europe’s response would likely follow a familiar playbook. After Trump imposed steel and aluminum tariffs on Europe during his first term, the EU hit back with its own tariffs on a range of U.S. products, including bourbon whiskey from Kentucky, the home state of then-Senate Majority Leader Mitch McConnell, a Republican.

European officials have also looked at what the bloc could offer to the U.S. on trade, including the possibility of greater cooperation on agricultural machinery, diplomats said. Cooperation countering China is another olive branch Brussels may offer Washington.

China, which the U.S. widely sees as an adversary both economically and militarily, promises to be a prime focus for Trump, starting with high tariffs.

New U.S. trade barriers would be painful for China’s economy. High tariffs would severely pinch trade with the U.S., perhaps by as much as 70%, according to Oxford Economics, reducing China’s share of U.S. imports to as little as 4%, from around 14% in 2023.

Chinese companies are in worse shape to weather higher tariffs than they were during Trump’s first term. Weak spending at home has contributed to almost two years of falling prices for manufactured goods, crushing corporate profit margins and pushing many firms into the red.

However, just as in the first phase of the trade war, Beijing has tools to lessen the hit from tariffs and for responding to the U.S. Policymakers could cut interest rates and extend tax rebates and other perks to exporters, economists say.

Like the EU, Beijing could also try to force the U.S. to reconsider trade actions by retaliating, potentially by raising tariffs on U.S. products such as motorcycles and bourbon, or by withholding supplies of critical minerals needed in high-tech industries such as chip making. It could also weaken its currency, enabling it to pick up market share in markets other than the U.S., economists say.

How much a second Trump administration will tap allies for help pressuring Beijing is a big question for Washington’s longtime friends.

South Korea bet big on the Biden presidency, with its leader singing “American Pie" at the White House last year and its corporate titans pouring tens of billions of dollars into the U.S.’s semiconductor, electric-vehicle and green energy sectors. That helped propel South Korea to a record-high trade surplus with the U.S. in the first half of 2024, rising about 55% year-on-year to roughly $29 billion, according to official Seoul estimates.

Now that looks like a tenuous spot with Trump, who has previously taken aim at trade imbalances with other nations and could tilt away from Biden’s industrial policy. The share prices of South Korea’s EV battery makers and solar-panel manufacturers nosedived on Wednesday.

North Korea is more of a wild card. During Trump’s first term, Kim Jong Un gave priority to sanctions relief and met with the U.S. leader three times. But after talks sputtered, Kim gave priority to self-reliance inside North Korea, then struck a tight pact with Putin that includes a recent deployment of troops. Pyongyang’s nuclear arsenal has only improved in recent years.

“Kim Jong Un may feel like he was completely betrayed by the American side" by Trump after their summits ended without a deal, said Sheen Seong-ho, an international-security professor at Seoul National University. “So he may take on a much tougher position."

Laurence Norman, James Marson and Benoit Faucon.

Write to Daniel Michaels at Dan.Michaels@wsj.com, Jason Douglas at jason.douglas@wsj.com, Kim Mackrael at kim.mackrael@wsj.com and Jiyoung Sohn at jiyoung.sohn@wsj.com