What to know about classified information as Signal chat fallout continues

Top Trump administration officials are facing a firestorm after using the commercially available app Signal to discuss a U.S. military attack on Houthi rebels in Yemen.

The administration's primary defense has been that there was no classified material shared on the message chain.

"There was no classified information as I understand it," President Donald Trump said earlier this week.

Several former military and intelligence officials, however, have rejected that assertion and argue the exchange could have put American troops at risk.

The Signal chat came to light after a reporter who was accidentally added to the discussion reported on it in The Atlantic and later released the specific messages involved.

The administration has not denied the authenticity of the texts, instead taking issue with how they were first described as "war plans" and criticizing the journalist involved. The reporter, Jeffrey Goldberg, has pushed back that the administration is playing a "semantics game."

What to know about classified information

An executive order signed by President Barack Obama in 2009 built out a "uniform system" for classifying and safeguarding sensitive national security and defense information.

There are three levels of classification: confidential, secret and top secret.

Jeffrey Fields, an associate professor at the University of Southern California who previously worked for the State and Defense departments, said designations are assigned based on how much damage would be done should the information be made public.

The Obama-era order gives the president, vice president and agency heads classification authority. All those figures must receive training on proper procedures for classification at least once a year, per the order.

"Declassification is more complicated than classification," Fields said.

While the president can declassify anything at any time, Fields said "declassification is generally done by the agency and officials there that originally classified the material."

Defense Secretary Pete Hegseth, in particular, is in the spotlight with his use of Signal to relay sensitive details on a pending strike. Hegseth sent details about which weapons systems would be used and the time the bombs would be dropped, according to the texts published by The Atlantic.

Director of National Intelligence Tulsi Gabbard and CIA Director John Ratcliffe testified this week that Hegseth would be the one to determine if information in the message chain was classified or not.

Hegseth was asked several times this week whether he declassified the information in the chat beforehand -- but he did not directly respond to the question.

"Nobody's texting war plans," he told reporters on Wednesday. "There's no units, no locations, no routes, no flight paths, no sources, no methods, no classified information."

Amid the debate over whether the messages were classified or not, some experts have noted that the information at the very least is sensitive in nature and should have been better protected.

"Some of the officials involved in this matter are contending that the information discussed was not classified. That is a big stretch," Fields said. "But even if that were true, you are still instructed to not talk about sensitive matters on open systems."

What happens when classified information is mishandled?

Questions have been raised about whether the Signal chat violated the Espionage Act, a 1917 law criminalizing unauthorized storage or disclosure of sensitive defense information.

Several administration officials, including Gabbard, Hegseth and Ratcliffe, have been sued by the nonpartisan watchdog American Oversight, which alleged they violated the Federal Records Act and the Administration Procedure Act by using Signal to discuss the military operation.

While the White House said it is conducting a review of the incident, particularly the mistake of adding a journalist to the chat, the Department of Justice and the FBI have not indicated that they will open any investigations.

ABC News Chief Justice Correspondent Pierre Thomas asked Attorney General Pam Bondi on Thursday if her department would probe the incident. Her response indicated that was not likely.

"What we should be talking about is it was a very successful mission," Bondi said. "Our world is now safer because of that mission."