The rapidity with which the United States Court of Appeals for the Federal Circuit issued an administrative stay on a ruling from the United States Court of International Trade enjoining the long list of tariffs Mr. Trump unveiled on “Liberation Day” underscores the unsettled reach of the president’s “emergency” powers. 

The injunction by the Court of International Trade against the Liberation Day tariffs, now frozen pending a ruling on the merits, struck a blow to the centerpiece of Mr. Trump’s economic agenda. The relatively obscure but powerful court found that the administration’s raft of tariffs exceeded “any authority granted” under a 1977 law known as the International Emergency Economic Powers Act.

The stay issued by the Federal Circuit means that the tariffs remain in force, though the reprieve for Mr. Trump could be short-lived if the appellate tribunal agrees with the district judges that the so-called reciprocal tariffs exceeded the president’s authority, even in a time of alleged emergency. The Supreme Court could soon involve itself in the case, as well — possibly in the form of an expedited appeal. 

In order to invoke the IEEPA, Mr. Trump declared a national emergency over America’s “large and persistent” trade deficit, which he determined amounts to an “unusual and extraordinary threat to the national security and economy of the United States.” The White House also cited emergency conditions with respect to fentanyl and immigration to impose additional tariffs on Canada, China, and Mexico. 

The first president to declare a national emergency was Abraham Lincoln, during the Civil War. The first president to issue a formal emergency proclamation was Woodrow Wilson, who in 1917 wrote that “I have found that there exists a national emergency arising from the insufficiency of maritime tonnage.” President Franklin Delano Roosevelt claimed an unbounded right to declare emergencies.

A case from 1952, Youngstown Sheet & Tube Co. v. Sawyer, denied President Truman’s ability to seize private steel mills during a time of national emergency — the war in Korea. The order was “not based upon any specific statutory authority, but was based generally upon all powers vested in the President by the Constitution and laws of the United States and as President of the United States and Commander in Chief of the Armed Forces.” 

In 1976 Congress passed the National Emergencies Act, signed into law by President Ford. The law ended all previously declared national emergencies and placed procedural limits on the president’s ability to act in emergencies. Every president since Ford has declared multiple such emergencies. The act as passed gave Congress a “legislative veto” over such declarations, but the Supreme Court in 1982 ruled that such vetos were unconstitutional.

Mr. Trump’s entire tariff program has not been wiped out. Those he imposed under the Trade Expansion Act of 1962 — on automobile parts, steel, and aluminum — still stand, and he can still impose 15 percent tariffs on countries where there’s a large trade deficit. But the long list of tariffs, enumerated country by country in the Rose Garden on Liberation Day, now await a final determination.

The administration argues that courts approved President Nixon’s tariffs in emergency circumstances in 1972, and that the declaration of an emergency is a “political” matter that is not justiciable in court. 

The DOJ notes in a court filing following the ruling: “Absent at least interim relief from this Court, the United States plans to seek emergency relief from the Supreme Court … to avoid the irreparable national-security and economic harms at stake.” A spokesman for the White House, Kush Desai, declares, “It is not for unelected judges to decide how to properly address a national emergency.”

The administration’s stance is that judicial interference with both tariffs and immigration policy amounts to encroachment on the president’s ability to set policy in those spheres. Vice President Vance told the Times earlier this month: “You cannot have a country where the American people keep on electing immigration enforcement and the courts tell the American people they’re not allowed to have what they voted for.” Messrs. Vance and Trump won some 49.8 percent of the popular vote. 

The high court has already been asked to weigh the lawfulness of Mr. Trump’s declaration of a species of emergency — an “invasion” — in respect of immigration. In February Mr. Trump declared a state of emergency at the nation’s southern border. In March, he invoked the 1798 Alien Enemies Act to deport Venezuelans accused of membership in the Tren de Aragua gang, a designated terror organization.  

Mr. Trump accused Tren de Aragua of being  a “hybrid criminal state that is perpetrating an invasion of and predatory incursion into the United States.” The declaration was in accordance with the requirement that the president must declare “a war between the United States and any foreign nation or government, or any invasion or predatory incursion is perpetrated, attempted, or threatened against the territory of the United States.”

The Supreme Court in May temporarily blocked the administration from deporting migrants under the AEA, reasoning that even under expedited procedures permitted by the statute some modicum of due process is still owed. The Nine, though, sent the case back down for further deliberations as to whether Mr. Trump’s declaration — and the powers he claimed — were lawful in the first place.