Navy Secretary Ray Mabus is expected on Tuesday to formally name a fleet replenishment oiler after gay-rights activist Harvey Milk, but one congressional critic says Mabus' name choice is putting politics ahead of the Navy's legacy.

Mabus will participate in a naming ceremony for the USNS Harvey Milk on Tuesday afternoon in Treasure Island, Calif. The oiler, which can carry 156,000 barrels of oil, is the first of six that will be built by General Dynamics NASSCO and will replenish Navy ships, as well as the aircraft deployed on them, while at sea.

The first ship in the class was named after civil rights icon Rep. John Lewis, D-Ga. The second ship, which will be delivered to the Navy in 2021, will be named after Milk, who served for four years in the Navy as a diving instructor before being elected to the San Francisco Board of Supervisors.

"T-AO 206 will, for decades to come, serve as a visible legacy of Harvey Milk's committed service to his nation, both as a sailor and as an activist. By adorning one of our ships with his name, his example will live on in the steel of that ship and in all those who will serve aboard her," Mabus is expected to say at the naming ceremony.

But Rep. Duncan Hunter, R-Calif., said the pick shows Mabus is playing politics with his ship names.

"What this says to the men and women of the Navy is that there wasn't one of you — at any time in history — who is more suitable for this honor. There are plenty of names out there to pick from, but Ray Mabus makes every decision with politics in his mind first and foremost, and that's a real disservice to men and women of the U.S. Navy and the service's legacy," Hunter said in a statement.

It's not the first time Hunter has been unhappy with Mabus' ship names. He previously criticized the secretary for naming a cargo ship after Cesar Chavez and a littoral combat ship after former Rep. Gabby Giffords, the congresswoman who survived a gunshot to the head.

Responding to criticism this year for naming a destroyer after former Sen. Carl Levin, D-Mich., Mabus said that he's "more a traditionalist than most of my predecessors."

"There's the John Stennis, an aircraft carrier, he was chairman of the armed services committee for years. There's the John Warner, a submarine, he was chairman of the Senate Armed Services Committee for years. There's the Carl Vinson, an aircraft carrier, he was chairman of the House Armed Services Committee for years," Mabus told the Washington Examiner.

"So this is a longstanding tradition to name Navy ships after members of Congress, particularly the heads of armed services committees from both the Senate and the House, but those who have gone above and beyond in terms of protecting particularly our servicemen and women."

Earlier on Tuesday, Mabus will name a guided-missile destroyer after John Basilone in a ceremony at Camp Pendleton, Calif. Basilone, a Marine gunnery sergeant, earned the Medal of Honor for valor during the Battle of Guadalcanal in World War II.

A previous ship named after Basilone was decommissioned in 1977.