The disclosure of a SEAL Team 6 mission into North Korea in 2019 has heightened interest in when the executive branch must tell congressional oversight committees about important military and intelligence operations.

The Trump administration did not inform Congress of what happened. But in 2021, the Biden administration decided to brief top congressional officials. The difference in approach raises the question of whether the Trump team improperly or illegally withheld the information.

President Trump, who had authorized the incursion by the SEAL team, addressed the matter publicly for the first time on Friday when asked about it by reporters in the Oval Office. “I could look but I know nothing about it,” Mr. Trump said. “I don’t know anything about it. I’m hearing about it for the first time.”

The rules for informing Congress about a high-stakes military or intelligence mission can be an ambiguous patchwork of statutes and informal norms, according to interviews with current and former officials in the executive and legislative branches. Already, there is a recurring tension between the president’s power to protect state secrets and Congress’s power of oversight.

Here is a closer look.

What happened?

A high-stakes commando mission went awry.

In 2019, a SEAL Team 6 unit slipped ashore into North Korean territory for a nighttime mission to plant a surveillance device. But the troops were unexpectedly interrupted by a boat. Fearing they had been discovered by security forces, they shot and killed everyone aboard the vessel; the North Koreans on the boat turned out to be unarmed civilians.

The New York Times reported on the previously secret episode this week.