A GOP member of the House Armed Services Committee is questioning naming a destroyer after former Sen. Carl Levin, arguing that it strays from traditional ship naming rules and politicizes the process.

Rep. Duncan Hunter, R-Calif., and a former Marine, sent a letter to Navy Secretary Ray Mabus on Tuesday asking for an explanation of how naming the USS Carl M. Levin after the Michigan Democrat reflects the sea service's ship-naming rules.

"It is important that the Navy adhere to its own ship-naming rules and take every effort necessary to avoid politicization of this process," Hunter wrote in the letter.

A Congressional Research Service report said destroyers are to be named for "deceased members of the Navy, Marine Corps and Coast Guard, including secretaries of the Navy."

Levin, who is still alive, served as chairman of the Senate Armed Services Committee during his 36 years in Congress, but never served in the military himself. He retired at the end of the last congressional session in 2014.

Senators in both parties praised naming the USS Carl M. Levin when it was announced last week.

"I can't think of a better person to name the ship after," Sen. Kelly Ayotte, R-N.H., said at a Senate Armed Services Committee

Mabus defended his decision to name the ship after Levin during the commissioning ceremony in Detroit on Monday.

"In the Navy, per traditional ship-naming convention, our destroyers are named after heroes," Mabus said in the prepared remarks. "As a champion for this nation, I know personally, as so many of you do, that Carl Levin has been a true hero to so many."

Hunter in the letter wrote that Levin was "a strong advocate for our men and women in uniform," and stressed that his complaint is about ship-naming traditions, not the senator's service.

Mabus' public affairs staff declined to respond directly to Hunter's letter, but noted that the secretary has named destroyers after several Medal of Honor and Navy Cross recipients during his tenure.

The Congressional Research Service report also states that there have been "numerous exceptions" to the traditional rules and that "a secretary's discretion to make exceptions to ship-naming conventions is one of the Navy's oldest ship-naming traditions."

In fact, exceptions to name ships after presidents or members of Congress occur so often that they are considered a "special cross-type naming convention," the report says.

Hunter has previously clashed with Mabus over ship names, including in 2011 over his naming the Lewis and Clark-class Navy cargo ship after labor organizer Cesar Chavez.