House Minority Leader Nancy Pelosi, D-Calif., warned Republicans Tuesday not to put language in a continuing spending resolution that gives retired Gen. James Mattis a waiver from current law that requires officers to be out of the military for seven years before they take on the role as secretary of defense.

Republicans are rumored to be considering adding that language to the CR, which was expected to be released on Thursday. But House aides said Tuesday that no decision has been made.

Pelosi argued that Republicans need to drop the idea.

"Civilian leadership of the military has been a cornerstone of our democracy since the founders, and for good reason," she said. "In the whole history of the Department of Defense, the only Defense secretary ever given a waiver was then-secretary of State, General George Marshall — who was provided an individual waiver in a stand-alone bill approved by the Congress."

Pelosi and Minority Whip Steny Hoyer, D-Md., encouraged Republicans to follow regular order if they are determined to circumvent the law that prevents recently active military leaders from running the Pentagon.

"Our view is it ought not to be in the CR," Hoyer said on Tuesday, referring to the continuing resolution Congress is expected to pass as early as this week to fund the government until March.

Even some House Republicans do not think a spending bill is the appropriate vehicle for such policy-shifting legislation, he said.

"It's really a matter for the Senate," Hoyer continued.

However, Hoyer did not say he opposes granting Mattis the waiver. "I haven't made a final decision," he said.