Washington ? In an action branded a backdoor draft by some critics, the military in the past several years has held tens of thousand of soldiers, sailors, airmen and Marines on the job and in war zones beyond their retirement dates or enlistment length.

It is a widely disliked practice that the Pentagon, under new Defense Secretary Robert Gates, is trying to figure out how to reduce.

Gates has ordered that the practice – known as “stop loss” – must “be minimized.” At the same time, he is looking for ways to decrease the hardship for troops and their families, recruit more people for a larger military and reassess how the active duty and reserves are used.

“It’s long overdue,” said Jules Lobel, vice president of the Center for Constitutional Rights and lawyer for some in the military who have challenged the policy in court.

“It has created terrible problems of morale,” Lobel said last week. “It has in some cases made soldiers feel that they were duped or deceived in how they were recruited.”

Gates has asked the chief of each service branch for a plan by the end of February on how they would rely less on stop loss.

The authority has been used off and on for years and was revived by all services to some extent after the attacks of Sept. 11, 2001.

As an example, the Army revived it in early 2002 to keep people with some skills or specialties deemed critical to the fight against terrorism and later used it to retain whole units, according to an Army chronology of the policy.

Pentagon officials provided no figures on how many people the policy has affected. Yet just in the Army, it is in the tens of thousands.

The Army Times newspaper reported in September that 10,000 soldiers were being held in the service at the time. That compared with 25,000 at one point in 2003.

The Defense Department says the main reason for the policy is to keep units whole for deployments, regardless of whether service time is up for some individuals in the unit.

“It’s based on unit cohesion,” former Defense Secretary Donald Rumsfeld once said when a soldier questioned him about the policy during a visit to a military base in Kuwait.

Though families dislike the policy and some troops oppose it, others accept it as a fact of life in wartime.