Democratic Congress Could Restrain Iran War, Not Tariffs, Osius Says

A Democratic-controlled Congress would likely curb President Donald Trump's ability to wage war in the Middle East but would struggle to unwind his tariffs, former U.S. ambassador to Vietnam Ted Osius said on Nov. 3. He spoke at Fortune's Southeast Asia 500 Summit in Ho Chi Minh City as U.S. voters headed to the polls for the midterms.

The war is a political liability. About 65% of Americans disapprove of Trump's handling of the U.S. military action in Iran, according to a Pew Research Center survey released on Oct. 8. That number was 61% in March, meaning the conflict has drawn majority disapproval since it began.

"The Iran war is extremely unpopular in the United States, and it's one of the factors that will be decisive in this election," said Osius, who served as ambassador to Vietnam from 2014 to 2017. "I expect that Congress would use the power of the purse to curb the president's ability to wage war in the Middle East."

Most polling averages put the Democratic Party ahead on the generic ballot. Several independent forecasts suggest Democrats will retake the House of Representatives; Senate control remains more uncertain. Even so, Osius framed a Democratic win as a verdict on Trump's coercive foreign policy.

Why can't Congress roll back the tariffs?

Tariffs are the harder target. Osius was blunt about the limits of legislative leverage: "I don't think we'll suddenly go back to the status quo ante. Unfortunately, it's actually harder to unwind tariffs once you put them in place."

A Democratic House and Senate might pressure the administration toward more predictable trade policy, but Osius conceded that tariff power "rests with the executive." That caveat matters. The Supreme Court ruled on Feb. 20 that Trump's tariffs imposed under the International Emergency Economic Powers Act, including his "Liberation Day" levies, were unlawful. The administration responded by switching legal justifications, imposing widespread duties citing allegations of forced labor and overcapacity.

"When you sort of run a state like a mobster, it may work in the short term, but in the long term it doesn't," Osius said. "It's much more effective, especially in this part of the world, to have predictable policies, and to show that rule of law and rules-driven trade works to everyone's benefit."

How has Southeast Asia absorbed the hit?

Trump's initial tariffs hit Southeast Asia harder than almost any other region in April 2025. Vietnam drew a 46% rate, based on its large trade surplus with the U.S., later cut to 20% in a deal. Southeast Asian governments have since negotiated with Washington, offering to lower their own trade barriers and buy more U.S. products.

The pressure has not dented Vietnam's growth. The country grew almost 10% in the third quarter of 2026, after 8.2% in the first quarter and 8.8% in the second. The Asian Development Bank expects developing Southeast Asia to grow 4.7% this year and 4.9% in 2027.

Jens Lottner, CEO of Vietnamese bank Techcombank, said exports are up 30% year-on-year despite the 12.5% tariff currently on Vietnamese goods entering the U.S. "If you're a bank, you're a proxy on the economy," he said. "We still have a couple of very good years ahead of us."

Amol Gupte, Asia South head at Citi, argued that global trade is not shrinking under the tariffs but being rerouted. "The aggregate amount of trade in the world is not really reducing; it's just changing flows," he said. "Exports from China to the U.S. have shrunk quite drastically, but China's aggregate exports have not reduced—they've actually grown substantially."

What risks remain for the region?

The region still sits at the center of several flashpoints. Lynn Kuok, the Lee Kuan Yew Chair in Southeast Asia Studies at the Brookings Institution, flagged tensions over ownership of the South China Sea. "We see off Vietnam's coast, for instance, a greater Chinese presence. And after a decade's pause, China is actually starting its rebuilding of islands off the Vietnamese coast," she said.

She added that the blockage of the Strait of Hormuz has exposed a second vulnerability: the Strait of Malacca, the narrow passage between Malaysia and Indonesia that carries much of Asia's trade. Malaysia, Indonesia, and Singapore have all pledged to keep it open. Still, she warned that "a future more nationalist government might actually seek to close off the strait, or come under pressure from various powers to close off the strait."

ASEAN members are invoking international law to defend their interests without picking sides in the Washington-Beijing rivalry. "They're not choosing U.S. or China; they're choosing principles of international law," Kuok said.

The midterms may check Trump's war powers, but on tariffs and Asia's trade map, the leverage stays in the White House.