The Republican-led Senate has approved a waiver to allow retired U.S. Marine Corps Gen. James “Mad Dog” Mattis to serve as incoming President Donald Trump’s secretary of defense.

Although he only retired in 2013, Gen. Mattis easily cleared an early procedural hurdle after his confirmation hearing, during which he described Russia as a “principal” threat against the United States.

Following the Senate Armed Services Committee’s bipartisan 24-3 vote, the full-chamber voted 81-17 vote to in favor of the waiver.

The only committee members who voted against his waiver are Democratic Sens. Kirsten Gillibrand (NY), Richard Blumenthal (CT) and Elizabeth Warren (MA).

Current law dictates that an individual must be out of military uniform for at least seven years before taking the civilian position of Pentagon chief.

The measure has only been waived for George Marshall in 1950.

“Having demonstrated 40 years of loyalty to the principle of civilian control and to the U.S. Constitution, I know what to expect from the uniformed leadership in their interactions with the Department’s civilian leaders,” Gen. Mattis told lawmakers in answers to policy questions posed before the confirmation hearing. “Furthermore, I understand what is required of the civilians tasked with leading our military services.”

“If confirmed as the Department’s civilian leader, I will put the right team in place to provide civilian leadership across the Department of Defense, ensure feedback loops are robust, and be responsive to the Congress,” also said Mattis, later adding, “Like all American commissioned officers, I was taught to respect the concept of civilian control of the military from my first day in uniform. I forecast no impact from my past service.”