What Is a War?

Key takeaways

• The Prize Cases (1863) created an enduring precedent for unchecked presidential war power. After Confederate troops fired on Fort Sumter in April 1861, Lincoln imposed a naval blockade of the South. This created a legal trap: a blockade under international law is only valid between two enemy nations at war, but Lincoln's official position was that the Confederacy was engaged in insurrection, not war (calling it a war might have given European powers grounds to recognize the Confederacy as sovereign). Four seized ships went to the Supreme Court, which ruled 5-4 that the blockade was constitutional and that when armed conflict is brought to the United States, the president is "not just authorized, but required by the Constitution to resist force by force," even without prior congressional approval. This is the only time the Supreme Court has ruled on presidential war power exercised without Congress, and every subsequent president has cited it to assert broad independent military authority.

• The War Powers Resolution (1973) aimed to check presidents who go to war without Congress, but it has never been effectively enforced. Passed over Nixon's veto, it requires the president to notify Congress within 48 hours of deploying military force, then stop within 60 days unless Congress formally authorizes the action (with a possible 30-day extension). Every president since Nixon has questioned whether the resolution is constitutional, while still formally complying with it. Trump sent a letter to Congress on September 4th, 2025, two days after the first boat strike. The letter acknowledged compliance with the War Powers Resolution but simultaneously asserted that Trump was acting under his own constitutional authority as commander-in-chief and did not need congressional approval—a pattern consistent with every modern president.

• At least 21 drone strikes have killed at least 83 people, treating drug trafficking as armed conflict. Starting September 2nd, 2025, U.S. military drones launched from naval ships struck boats in international waters allegedly linked to Tren de Aragua, a Venezuelan criminal gang the Trump administration designated as a foreign terrorist organization. The administration labeled those killed "combatants" in an armed conflict with non-state actors. But these individuals were not in uniform, not organized as a military force, and not engaged in any sustained campaign against the United States. Drug trafficking is a federal crime normally addressed through Coast Guard interdiction, arrest, and prosecution. The boat strikes bypassed all of that. Two people survived and were returned to Ecuador and Colombia.

• The Justice Department used a two-part legal test developed under Obama to justify the strikes. In 2011, the Obama administration's Office of Legal Counsel wrote a memo arguing the president has constitutional authority to use military force without congressional approval whenever two conditions are met: the action serves "important national interests," and it does not rise to "war in the constitutional sense." OLC wrote the memo to justify U.S. participation in a NATO coalition enforcing a UN-authorized no-fly zone over Libya, a specific and internationally backed intervention aimed at protecting civilians from a documented government crackdown. The Trump Justice Department applied the same two-part test to the Caribbean boat strikes, showing how broadly worded legal standards crafted for one administration's limited action can be repurposed in a far more extreme context.

• A disputed definition of "hostilities" has allowed the administration to sidestep the 60-day deadline. The War Powers Resolution's clock only starts when U.S. forces enter "hostilities or situations where imminent hostility is clearly indicated." The statute never defines the term. The Obama administration exploited that gap in 2011, arguing that drone strikes in Libya didn't qualify as hostilities because Libyan forces couldn't realistically shoot back at U.S. aircraft. In November 2025, the Trump Justice Department made the same argument to Congress: the boat strikes don't count as hostilities because the people in the boats can't fire back at drones. The logic cuts against itself—the administration calls those people combatants to justify killing them, then argues the engagement isn't hostile enough to trigger congressional oversight.

• Congress has the legal tools to stop these strikes but has shown no sign of using them. The Supreme Court consistently declines to rule on war-power disputes between branches, treating them as political questions. Congress's most direct option would be cutting off funding for the strikes. No Congress has done this in any comparable situation. The 2001 AUMF, passed days after 9/11 and still in effect today, has been used to justify military operations against groups that didn't exist in 2001 and is now described as the foundation of America's "forever wars." Without a Congress willing to assert itself, the war-power question remains structurally unresolved, and the cost of that unresolved question is now measured in lives.

People, organizations, products, and links mentioned

• Roman Mars, host
• Elizabeth Jo, professor and constitutional law expert
• Abraham Lincoln
• Barack Obama
• Richard Nixon
• Tren de Aragua (TDA), Venezuelan criminal gang designated as a foreign terrorist organization by the Trump administration in March 2025
• The Office of Legal Counsel (OLC), the Justice Department unit that provides legal advice to the president
• The New York Times (cited for reporting on the Justice Department memo justifying the strikes)
• NATO
• The UN Security Council
• The Prize Cases (1863 Supreme Court decision)
• The War Powers Resolution (1973)
• The 2001 Authorization for the Use of Military Force (AUMF)
• The Amy Warwick, Hiawatha, Briante, and Crenshaw (the four ships seized in 1861 whose cases became the Prize Cases)

Notable moments

• The episode opens with what sounds like a trivial question, "Was the Civil War a war?" In 1863, the answer had enormous legal stakes. A "yes" risked giving European powers grounds to recognize the Confederacy as a sovereign state. A "no" meant Lincoln's blockade was illegal and his authority to issue the Emancipation Proclamation collapsed with it.

• The Supreme Court ruled 5-4 in the Prize Cases that the Civil War qualified as a war, holding that when armed conflict comes to the United States, the president is "not just authorized, but required by the Constitution to resist force by force." It remains the only time the Court has ruled on presidential war power used without prior congressional authorization.

• Trump's September 4th letter to Congress ticked the 48-hour notification box, then immediately undercut the gesture by stating he was acting solely under his authority as commander-in-chief. The professor notes this is "very similar to what all other modern presidents have said" in their own notices.

• Mars grows visibly frustrated at the circular logic: the administration calls the people in the boats "combatants" to justify killing them, then argues the strikes don't count as "hostilities" because the same people couldn't shoot back. "That is so infuriating in both cases," he says.

• On learning the 2001 AUMF is still in effect and has been applied to groups that didn't exist when it passed, Mars responds simply: "Wow." The professor replies: "Yep."

• The professor warns that treating everything as an emergency ultimately means emergency powers never end: "The problem is when everything is an emergency, as the Trump administration keeps asserting, then this expansive power is never going to end."

• Mars makes the structural point the episode builds toward: the Constitution "wasn't built around parties. It was built around opposing branches," and when Congress stops asserting itself as the loyal opposition to executive overreach, there is nothing left to constrain a president unwilling to recognize limits.

Time saved: 36 minutes.