A federal appeals court agreed on Tuesday to allow President Trump to maintain many of his tariffs on China and other U.S. trading partners, extending a pause it granted shortly after another panel of judges ruled in late May that the import taxes were illegal.

The decision, from the U.S. Court of Appeals for the Federal Circuit in Washington, delivered an important but interim victory for the Trump administration. The government still must convince the judges that the president appropriately used a set of emergency powers when he implemented the centerpiece of his economic agenda.

The decision came as negotiators from the United States and China agreed to a framework intended to extend a trade truce between the two superpowers. The Trump administration had warned that those talks and others around the world would have been jeopardized if the appeals court had not granted a stay while arguments proceeded.

At the heart of the legal wrangling is Mr. Trump’s novel interpretation of a 1970s law that he used to wage a global trade war on an expansive scale. No president before him had ever used the International Emergency Economic Powers Act, or IEEPA, to impose tariffs, and the word itself is not even mentioned in the statute.

But the law has formed the foundation of Mr. Trump’s campaign to reorient the global economic order. He has invoked its powers to sidestep Congress and impose huge taxes on most global imports, with the goal of raising revenue, bolstering domestic manufacturing and brokering more favorable trade deals with other countries.

A group of small businesses and a coalition of states in April each sued the Trump administration in the U.S. Court of International Trade, claiming that they faced financial hardship from the president’s illegal actions. The trade court agreed, finding late last month that Mr. Trump had greatly overstepped the bounds of the emergency powers law.

The judges ordered the White House to halt many of its tariffs, including those imposed on China, Canada and Mexico. But the Trump administration immediately appealed the ruling, and judges on the appeals court initially granted the government a temporary stay. That allowed the president’s tariffs to remain in place, while the court began to evaluate the government’s request for a longer-term pause on original ruling.

It granted that motion on Tuesday, allowing the court to turn next to the legal arguments at the heart of the case — and the extent to which Mr. Trump possesses the sweeping trade powers that he claims.