() The U.S. Supreme Court may soon wade into the legal dispute that pits President Trump against civil libertarians who oppose his use of a wartime-powers law from the 18th century.

Congress originally passed the Alien Enemies Act of 1798 as the U.S. was poised to go to war with France. The law grants a U.S. president the power to summarily detain or deport non-citizens deemed a threat during wartime.

The law was last used during World War II, when President Franklin D. Roosevelt ordered the relocation and incarceration of 120,000 Japanese Americans while the U.S. fought Japan. A smaller number of German nationals and German Americans were also detained.

The facts surrounding the Trump administration’s attempt to invoke the act are different. Here are key events leading up to the current legal challenge.

March 14, 2025

President Trump privately signs a proclamation invoking the Alien Enemies Act after the State Department designated certain cartels and gangs as terrorist organizations. Among the terror groups is Tren de Aragua (TdA), a Venezuelan gang.

In a document shared the following day, the Trump administration argues the Venezuelan government is effectively fighting a proxy war through TdA on U.S. soil. He announces plans to use the act to apprehend and remove Venezuelan migrants who are members of the gang.

March 15

The American Civil Liberties Union and Democracy Forward filed suit early on Saturday, March 15, hoping to prevent the Trump administration from using the Alien Enemies Act, saying it’s an overreach without a formal declaration of war.

U.S. District Court Judge James Boasberg sets a 5 p.m. emergency hearing. Around 6:45 p.m., he says he’ll issue a temporary restraining order barring the Trump administration from deporting noncitizens under the AEA and tells Justice Department lawyers that planes must return if they’ve already departed. The order is put in writing around 7:30 p.m.

Two planes carrying more than 250 alleged migrant gang members arrived later that night in Honduras before proceeding to El Salvador. White House officials will claim the aircraft were over international waters at the time of the judge’s decision.

March 16

The Salvadoran government posts widely seen videos of detainees being received under heavy guard and being transferred to a notorious maximum-security prison, where they will be held for at least one year for $6 million.

The president of El Salvador posts a taunting tweet about the U.S. judge’s order, saying, “Oopsie … Too late,” with a laughing emoji.

March 17

Judge Boasberg begins grilling Justice Department representatives about whether the Trump administration ignored his order, setting in motion a series of contentious hearings in which government attorneys try to invoke national security reasons to avoid disclosing more information.

March 18

President Trump blasts Boasberg on his social media platform, Truth Social, saying the federal judge should be impeached. In response, Chief Justice John Roberts offers a rare public statement, saying calls for impeachment is not “an appropriate response” when someone disagrees with a judicial decision.

March 19

As observers wonder if a constitutional crisis is at hand, Trump’s border czar Tom Homan, tells that federal authorities will abide by the judge’s temporary order as parties argue their positions in court. Deportations would continue through other means, said Homan, who denied allegations that some migrants without gang ties had been swept up in the March 15 flights to El Salvador.

March 26

U.S. Homeland Security Secretary Kristi Noem visits the Salvadoran prison where Venezuelans were sent by the Trump administration. She films a video there warning migrants about coming to the U.S. illegally.

A federal appeals court upholds Judge Boasberg’s order in a 2-1 ruling.

March 28

In an emergency appeal, the Justice Department asks the U.S. Supreme Court for permission to resume deportations of Venezuelan gang members under the Alien Enemies Act.

Boasberg extends his restraining order blocking the deportations.