US senator sues Pentagon over alleged retaliation for political speech

A senior US senator has taken the Trump administration to court, accusing the Pentagon of launching an unprecedented campaign of political retaliation that he says tramples free speech and threatens the constitutional separation of powers.

Senator Mark Kelly filed a lawsuit on Monday in federal court in Washington, DC, against the Department of Defense and its secretary, Pete Hegseth, as well as the Department of the Navy and its secretary, John Phelan. The complaint alleges that the administration has engaged in “punitive retribution” aimed at silencing Kelly for protected political speech.

“I filed a lawsuit against the Secretary of Defense because there are few things as important as standing up for the rights of the very Americans who fought to defend our freedoms,” Kelly, a military veteran, said in a statement posted on social media.

The case marks the latest escalation in a confrontation that began in November, when six Democratic lawmakers with military or intelligence backgrounds released a video reminding US service members of their duty to refuse illegal orders. The message echoed long-standing legal precedent and military doctrine, which hold that troops are obligated to reject orders that violate US law or the Constitution.

President Donald Trump and his allies, however, denounced the video as “seditious behaviour” and demanded consequences for the lawmakers involved.

Kelly, a Democratic senator from the swing state of Arizona, has borne the brunt of the backlash. He is one of the most recognisable figures in the video and is widely seen as a rising force in Democratic politics, with speculation already swirling about a possible presidential or vice-presidential bid in 2028.

Before entering politics, Kelly served 25 years in the US Navy, flying combat missions during the Gulf War and retiring with the rank of captain. He later became a NASA astronaut, serving alongside his twin brother, Scott Kelly. His political career began after his wife, former Congresswoman Gabby Giffords, survived a 2011 assassination attempt.

“My wife Gabby was always the elected official in our family,” Kelly told the Senate on Monday. “If she had never been shot in the head, she would be here in this chamber and not me.”

Since the November video, Kelly has faced a series of actions from the Trump administration that his lawsuit characterises as unconstitutional. Shortly after the video’s release, the Defense Department announced it was investigating him and warned that he could face a court-martial depending on the outcome.

That pressure intensified this month when Hegseth revealed he had submitted a formal letter of censure accusing Kelly of “conduct unbecoming of an office” and of undermining military discipline. The letter called for Kelly to be demoted retroactively and to have his military retirement pay reduced.

“Senator Mark Kelly — and five other members of Congress — released a reckless and seditious video that was clearly intended to undermine good order and military discipline,” Hegseth wrote on X. “As a retired Navy Captain who is still receiving a military pension, Captain Kelly knows he is still accountable to military justice.”

Kelly rejects that claim, arguing that the administration is weaponising military authority to punish dissent.

“Pete Hegseth is coming after what I earned through my twenty-five years of military service, in violation of my rights as an American, as a retired veteran, and as a United States Senator,” Kelly wrote on Monday. “His unconstitutional crusade against me sends a chilling message to every retired member of the military.”

In court filings, Kelly argues that the effort to discipline him violates not only his First Amendment rights but also the constitutional principle of legislative independence, by attempting to intimidate a sitting member of Congress.

“It appears that never in our nation’s history has the Executive Branch imposed military sanctions on a Member of Congress for engaging in disfavored political speech,” the lawsuit states.

The complaint also raises due process concerns, pointing to public statements by Trump that appeared to prejudge the case. One social media post by the president described Kelly’s actions as “SEDITIOUS BEHAVIOUR, punishable by DEATH”.

Kelly’s lawyers argue that Hegseth’s censure letter effectively announced guilt before any neutral review could take place.

“The Constitution does not permit the government to announce the verdict in advance and then subject Senator Kelly or anyone else to a nominal process designed only to fulfill it,” the lawsuit says.

Kelly is asking the court to halt any disciplinary proceedings and to declare the censure unlawful, setting up a high-stakes legal test of whether a US administration can use military mechanisms to punish political speech by elected officials.