Defense Secretary Jim Mattis used tough terms to back up the new deploy-or-get out rules, saying those held back for administrative reasons place an unfair burden on troops who routinely serve multiple combat tours.

"You're either deployable, or you need to find something else to do. I'm not going have some people deploying constantly and then other people, who seem to not pay that price, in the U.S. military," Mattis told reporters traveling with him on his way home Saturday from a week-long trip to Europe.

"If you can't go overseas [and] carry a combat load, then obviously someone else has got to go. I want this spread fairly and expertly across the force," he said.

Defense Department officials have said there will be numerous exceptions to the new rules forcing out service members unable to deploy for 12 consecutive months -- including waivers for those wounded in combat and those who are pregnant -- but Mattis is firm on the overall concept.

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Troops who routinely deploy "need time at home, they need time with their families. We may enlist soldiers, but we re-enlist families. That's the way it is," he said.

"If you can't keep the family together, then you're either going to lose the family or you're going to lose the soldier, and that's a net loss for our society and for our military," Mattis said.

His major concern, he said, is for the DoD to find ways for those wounded or injured in the field to continue to serve, if that is their choice.

"We'll find a place to use them. That's a special category. They've earned that special status," he said.

The DoD's new deploy-or-out rules, first reported by Military Times, were disclosed by Army Command Sgt. Maj. John Troxell, the senior enlisted adviser to Joint Chiefs Chairman Gen. Joseph Dunford.

Troxell said about 11 percent -- or 235,000 -- of the 2.1 million personnel serving on active duty, in the reserves or National Guard are currently non-deployable.

Of that 235,000, about 99,000 are on the list for administrative reasons, such as not having all their immunizations or required dental exams. About 20,000 are not deployable due to pregnancy, and 116,000 are not deployable due to either short- or long-term injuries or wounds, Troxell said.

Robert Wilkie, undersecretary of defense for personnel and readiness, gave different numbers in testimony last week to the Senate Armed Services subcommittee on personnel. He said up to 286,000 service members could potentially face being forced out of the military.

"This new policy is a 12-month deploy or be removed policy," he said, with exceptions for pregnancies and wounded troops cleared to remain in the military by medical boards.

"On any given day, about 13 to 14 percent of the force is medically unable to deploy -- that comes out to be around 286,000 service members," Wilkie said.

The new policy stems from Mattis' directive to the services last summer to take steps to improve the "lethality" of the force.

In justifying the major policy initiative, Wilkie said, "The situation we face today is really unlike anything we have faced -- certainly in the post-World War II era. We have to ensure, given the climate this country faces, that everyone who signs up can be deployed anywhere in the world."

In a department-wide memo released Thursday on "Retention Policy for Non-Deployable Service Members," Wilkie said he would also seek to establish "standardized criteria for retaining non-deployable service members."

However, "service members who have been non-deployable for more than 12 consecutive months will be processed for administrative separation," the memo states. In addition, the services do not have to wait until a service member has been non-deployable for 12 consecutive months to begin the separation process.

As for exceptions, the memo states the service secretaries will be "authorized to grant a waiver to retain in service a service member whose period of non-deployability exceeds the 12 consecutive months limit."

Wilkie gave the services until Oct. 1 to implement the new policy, but said they also could begin separating non-deployable personnel immediately, at their discretion.

During his flight home, Mattis gave several examples of why he thought the old rules on deployments are unfair to those who go again and again into war zones.

"Let me explain what happens: If you have 100,000 troops -- let's just pick a number, just for the sake of giving you [a] mental model of this -- if 10,000 of them are not deployable, then 90,000 deploy more often, obviously to meet the same deployment standard. So that's unfair."

He spoke of meeting a woman who told him that "her husband was on -- who is preparing -- no, is on his sixth deployment, completing his fifth, and is now on his sixth combat deployment."

"This lady had been married to the soldier for 11 years, OK? When that sort of thing happens, that brings sharply into focus that some people are carrying more than the share of the load that I want them to carry," Mattis said.

"But the bottom line is, we expect everyone to carry their share of the load and, you know, sometimes things happen, people bust their legs in training or they're in a car accident, we understand that, and if they -- sometimes that even takes months of recovery," he said.

"We understand that. But this is a deployable military. It's a lethal military that aligns with our allies and partners," and boosting the overall lethality of the force is the major issue, he added.

Mattis said the Army was the catalyst in convincing him to adopt new rules on deployments.

Wilkie "defined the problem that initially was brought to his attention by the U.S. Army, where they had many non-deployables on their rolls," Mattis said.

"I'm not talking about combat injured now. That's a separate category. But people who are, just for one reason or another, are not able to deploy with their units," he said. "It was a significant number, and the Army brought their concerns forward. The other services also highlighted the concerns."

-- Richard Sisk can be reached at Richard.Sisk@Military.com.