Lawmakers from both sides of the aisle and in both chambers of Congress say they're concerned ongoing operations against alleged "narco-terrorist" boats could be unlawful.
Leaders of the Senate and House Armed Services Committees — both controlled by Republicans — said they're investigating the strikes.
"People are very concerned about these strikes and the manner in which they're occurring," Alabama Rep. Mike Turner, who sits on the House Armed Services Committee, told CNN Tuesday.
Senate Armed Services Committee Chair Sen. Roger Wicker and ranking Democrat Sen. Jack Reed issued a joint statement promising oversight.
"The Committee has directed inquiries to the Department, and we will be conducting vigorous oversight to determine the facts related to these circumstances," the statement said.
Renewed calls for oversight of the strikes follow reports last week that two survivors of a Sept. 2nd strike on an alleged drug trafficking boat were killed while clinging to debris in the water. It was the first of more than 20 such strikes that have reportedly killed at least 71 people.
A Washington Post report, confirmed by NPR, said Defense Secretary Pete Hegseth ordered there be no survivors — something that, if true, would be illegal under the Law of Armed Conflict.
"As a general legal principle of the law of war, law of armed conflict, those type of orders are unlawful," said San Diego military attorney Edward O'Brien.
O'Brien served 27 years in the Navy as a Judge Advocate General. His assignments including tours as Staff Judge Advocate of a carrier strike group and of the Combined Joint Task Force Horn of Africa. He advised military commanders on the rules of engagement and taught the Law of Armed Conflict at the Naval War College as an adjunct professor.
"You can't issue sort of a 'kill everyone' order," O'Brien said. "Issuing an order that there shall be no survivors is a direct violation of the law of armed conflict."
Hegseth denied issuing the order Monday, saying Navy Adm. Frank Mitchell Bradley ordered the second strike Sept. 2.
"Admiral Mitch Bradley is an American hero, a true professional, and has my 100% support," Hegseth said on X. "I stand by him and the combat decisions he has made — on the September 2 mission and all others since."
On Tuesday, sitting next to President Donald Trump, Hegseth said he didn't see the second strike.
"I watched that first strike live," Hegseth said. "As you can imagine, the Department of War, we got a lot of things to do. So I didn't stick around for the hour and two hours — whatever ..."
O'Brien said even if the law of armed conflict applies to alleged drug traffickers — there are questions as to whether they qualify as armed combatants.
"Absent an armed conflict, international human rights law would apply to what they're doing — and there are significant issues with that," O'Brien said.
The Trump administration says the United States is in a "non-international armed conflict" and the alleged traffickers are legal targets.
If the alleged smugglers are legitimate combatants, O'Brien said, it still doesn't justify killing survivors of an airstrike while they cling to the burning wreckage of their boat.
"It's a long-standing principle — (going) back to the Geneva Conventions and even before that," O'Brien said. "Military members — sailors in particular — in the water are out of combat. (They) are non-targetable. And in fact, under international law and United States Navy traditions and requirements, you're supposed to render aid when possible."
O'Brien said the Pentagon would need to prove the survivors continued to demonstrate hostile intent or action to justify further attacks on them.
"Under these circumstances, if they were, in fact, clinging to a raft or wreckage, it's hard to see how they posed any threat whatsoever," he said.
There is historic precedent for the rules.
During World War II, a German U-boat sank the Greek steamer SS Peleus in the Atlantic Ocean. U-boat commander Lt. Heinz Eck ordered his crew to fire machine guns at survivors and throw grenades into the life rafts.
Five of the German sailors were tried and found guilty of war crimes. Three of them — including Eck — were executed by firing squad.
San Diego Democratic Rep. Sara Jacobs also serves on the House Armed Services Committee. She told KPBS Wednesday she believes the operations against alleged drug smugglers to be unlawful.
"I have been briefed," Jacobs said. "I have read the legal opinion. What I can say is that their legal argument is not convincing — it is bonkers, truthfully."
Service members can be prosecuted for following unlawful orders — the so-called "Nuremberg Defense" of "just following orders" isn't valid.
"In the Uniform Code of Military Justice it says that if a service member follows an unlawful order they are liable to be prosecuted," Jacobs said.
She says it's important Congress exercise its oversight duty to protect service members from being placed in a position where they are questioning the lawfulness of orders.
"There is not a statute of limitations on the UCMJ," Jacobs said.
Military attorneys have told KPBS it's difficult for troops to question orders because the presumption is orders are lawful.
"The law is clear that you disobey an order at your peril," O'Brien said. "If you're wrong, it's not a defense to say 'I thought it was an illegal order.' It either is or it is not. But if it is not and you carry it out, there is no defense that 'I was just obeying my superiors.'"
Jacobs said she expects briefings over the next couple weeks but that public hearings haven't yet been scheduled.
