WASHINGTON — One day after a federal court declared many of his tariffs to be illegal, President Donald Trump and his top aides rushed Thursday to resuscitate the centerpiece of the administration’s trade agenda, seeking to restore their ability to use the threat of eye-watering import taxes to force other nations into submission.

Since taking office, Trump had relied on a federal emergency powers law as a form of political leverage, hoping to use sky-high duties — or the mere threat of them — to force other governments to make trade concessions.

Late Wednesday, however, a little-known and highly specialized U.S. Court of International Trade dealt an early yet significant blow to that strategy. The bipartisan panel of judges, one of whom had been appointed by Trump, ruled that the law did not grant the president “unbounded authority” to impose tariffs on nearly every country, as Trump had sought.

Shortly after that ruling, the administration petitioned two sets of judges to allow it to continue imposing its tariffs, reflecting a growing fear throughout the White House that a legal defeat could severely undercut its capacity to wage a global trade war.

The administration quickly asked the court to pause any enforcement of its order as it embarked on an appeal at the U.S. Court of Appeals for the Federal Circuit, where it similarly sought emergency relief.

The appeals court did just that, temporarily halting the order from a federal trade court issued a day before, allowing Trump, for now, to maintain many of the tariffs he has imposed on China, Canada and Mexico and preserve the threat of “reciprocal” rates, which he announced on most nations and then suspended in early April.

In a filing submitted Thursday, the Justice Department said the new order invalidating its claims of sweeping trade powers was “rife with legal error.” The government warned it would hamstring Trump’s efforts “to eliminate our exploding trade deficit and reorient the global economy on an equal footing.”

Before the appeals court decision, White House press secretary Karoline Leavitt opened her Thursday briefing by attacking judges for having “brazenly abused their judicial power.” Indicating the fight was far from over, she noted: “The Supreme Court must put an end to this for the sake of our Constitution and our country.”

Just before she spoke, a federal judge in a separate case ordered another, temporary halt to many of Trump’s tariffs, ruling in favor of an educational toy company in Illinois, whose lawyers told the court it was harmed by Trump’s actions.

Judge Rudolph Contreras, the district judge presiding in the case, concluded the economic powers law “is not a law providing for tariffs,” though he stayed the start of his preliminary injunction for the next 14 days.

Despite Thursday afternoon’s victory for the White House, the string of new court defeats only reinforced a palpable sense of worry across the administration, after some of Trump’s top advisers had previously told judges hearing the cases that an adverse decision could hamstring their negotiations. Top White House aides said in April that it planned to reach 90 deals in 90 days, with a deadline of mid-July, and the administration appears far from reaching its goal.

“If this court limits that authority, foreign counterparts will have reduced incentives to reach meaningful agreements — resulting in the status quo that led to the national emergency,” Secretary of Commerce Howard Lutnick said in a declaration filed with the trade court last week.

Kevin Hassett, the director of the White House National Economic Council, downplayed the consequences of the late Wednesday court ruling, casting it Thursday morning as one of a few “little hiccups here and there.”

Hassett said that the president had other legal tools to impose tariffs outside the economic emergency law, though he signaled that the administration was “not planning to pursue those right now.”

“It’s certainly not going to affect the negotiations. Because, in the end, people know President Trump is 100% serious, and they also have seen President Trump always wins,” he said.

And yet, even with the temporary lifeline extended Thursday afternoon, the president’s earlier court defeat left the future of his global trade war in great doubt.

Around the world, foreign leaders scrambled to decipher the decision and how it might affect their talks with the United States. More than a dozen countries are involved in talks with the administration, which is demanding that other nations lower their taxes and restrictions on U.S.-made goods in exchange for a reduction in tariffs.

None of the lawsuits that have been decided against the president implicate Trump’s other tariffs, which are issued under separate legal authorities. They include his levies on steel, aluminum and cars, as well as other tariffs that the president has threatened on pharmaceuticals, semiconductors and other critical products.

Taken together, the nation’s effective tariff rate would fall to 7% from 18% if Trump cannot reinstate his steepest duties, according to Ernie Tedeschi, the director of economics at the Budget Lab at Yale. That would still be the highest tariff rate since 1969.

While Tedeschi described it as a “major dial down” on trade, he said the remaining tariffs could still shrink the rate of the nation’s economic growth and raise prices for consumers. “That’s still a substantial impact,” he said.