Rep. Thomas Massie (R-Ky.) introduced a resolution Tuesday to impeach Defense Secretary Pete Hegseth, accusing him of defying Congress and illegally continuing the U.S. war in Iran.

Why it matters: The impeachment effort is a long shot in the GOP-controlled Congress, but Massie's resolution is privileged, meaning he can force a full House vote and put Republicans on the record over Hegseth's handling of the Iran war.

  • It's a dramatic escalation in the retiring lawmaker's months-long push to rein in the Trump administration's war powers. Massie did not give GOP leaders a heads-up on his plans.
  • The effort also comes after the House has repeatedly voted on efforts to constrain the administration's military campaign in Iran, including passing war powers resolutions in June and July directing the president to end U.S. hostilities with Tehran.
  • The House is slated to vote Tuesday on another war powers resolution on the Iran war effort.

Driving the news: Massie's resolution accuses Hegseth of carrying out orders to continue operations in Iran despite Congress' constitutional authority over war and its votes seeking to end the conflict.

  • Massie argued Hegseth's actions "frustrated Congress's ability to exercise its most solemn constitutional responsibility" and allowed an "unlawful war" to continue.
  • "In all of this, Secretary Hegseth has acted in a manner contrary to his trust as Secretary of Defense," Massie said on the House floor.
  • The eight-article resolution also targets Hegseth over U.S. military operations in Venezuela and Yemen, including accusing him of illegally directing the operation to capture Venezuelan President Nicolás Maduro without congressional authorization.

Zoom out: Hegseth already faced a separate impeachment push from House Democrats, who introduced six articles against him in April that included allegations he waged an unauthorized war against Iran.

What's next: The House will have to take up the legislation within the next two legislative days, but GOP leaders could also move to vote on tabling the resolution instead.

Editor's note: This story has been updated to say that Massie didn't let GOP leaders know in advance about his plans.