The Pentagon has announced an investigation into Arizona Senator Mark Kelly, a retired Navy captain, following his participation in a video where Democratic lawmakers urged U.S. troops to refuse illegal orders.
This move comes after President Donald Trump accused the participants of seditious behavior.
The defense department cited potential breaches of military law that could affect the loyalty, morale, or discipline of the armed forces.
Kelly, who served as a fighter pilot and astronaut, remains subject to the Uniform Code of Military Justice as a retiree.
In the video posted last Tuesday, Kelly and five other Democrats with military or intelligence backgrounds addressed service members directly.
They emphasized the obligation to uphold the Constitution and refuse unlawful commands.
The Pentagon's statement highlighted that retired service members like Kelly can be recalled to active duty for court-martial or other actions.
Defense Secretary Pete Hegseth described the video as despicable, reckless, and false, arguing it undermines good order and discipline.
Hegseth noted that Kelly is the only participant still under UCMJ jurisdiction.
The investigation stems from allegations of misconduct, though specific charges were not detailed.
Kelly responded that the probe would not intimidate him from holding the administration accountable.
He referenced his combat experience and NASA service, including recovering bodies from the 2003 Columbia shuttle disaster.
Trump reacted strongly on Truth Social, calling the actions seditious and punishable by death, while reposting a message suggesting execution.
Kelly expressed concerns for his family's safety, citing his wife Gabrielle Giffords' 2011 assassination attempt and recent political violence.
The Pentagon has undergone purges of senior officials, including the Joint Chiefs chairman and others.
Democrats have criticized Trump's military strikes on drug traffickers and raised fears of potential war with Venezuela.
Republicans generally support Trump's stance, while opponents condemn it.
The case raises questions about free speech, separation of powers, and the military's apolitical nature.
Trump's administration has targeted critics, including former officials like John Bolton and James Comey.
The Pentagon reminded all service members of their duty to obey lawful orders, which are presumed legal.