A female Ranger student, crouching left, waits to climb a cliff on Mount Yonah in northern Georgia. She will be one of the first two female graduates of the Ranger course on Friday. (Dan Lamothe/The Washington Post)

The graduation this week of two female soldiers from the Army’s famously difficult Ranger School has put new pressure on the U.S. military to make women eligible to serve across its combat ranks, current and former U.S. officials said.

The historic achievement by the two women, who are expected to be awarded the prestigious Ranger Tab at a ceremony on Friday, comes amid a sweeping assessment at the Pentagon that is expected to lead to the removal of long-standing barriers to female soldiers across the armed services.

How far and fast those gender boundaries shift is expected to become evident within months, when each branch of the military is required to submit a petition to senior leaders in the Pentagon listing the dwindling set of jobs that they want to remain all-male, with detailed justifications required for every category from which women would be excluded.

There are already emerging signals on how some of the services plan to proceed. Each of the services is considering changes to physical requirements for certain positions that could enable greater female participation — a move that some have resisted out of concern that it would erode standards in place for decades.

Military history was made as two women passed the U.S. Army's grueling 62-day Ranger Course in Fort Benning, Ga. (Reuters)

The Army’s decision to allow women to attend Ranger School this year was seen by many as an unambiguous signal from a military branch that nevertheless has yet to allow females to serve in its elite units, including its 75th Ranger Regiment, a light-
infantry force of about 3,600 soldiers.

The graduations this week of Kristen Griest, a military police officer from Orange, Conn., and Shaye Haver, an Apache helicopter pilot from Copperas Cove, Tex., make that ban on female Rangers increasingly precarious and could accelerate broader changes across the Army.

The completion of the Ranger course by two female West Point graduates punches holes in arguments that women are not capable of serving in the infantry or other physically demanding jobs, said retired Army Lt. Gen. David Barno, who commanded troops as a general in Afghanistan and served earlier in his career in Ranger battalions.

“From the first moment a woman pins on a Ranger Tab,” Barno said, “it is game over on the discussion about keeping women out of the military.”

In 2013, then-Defense Secretary Leon Panetta lifted a long-standing ban on women serving in combat roles but gave each of the armed forces until January 2016 to seek exemptions for certain jobs to remain male-only. Under Panetta’s order, the chiefs of the Army, Navy, Air Force and Marines would have to formally justify why those positions should remain closed to women.

Defense Secretary Ashton B. Carter, a civilian who never served in the military, is expected to rule on each request by January with guidance and feedback from senior military officials. Marine Gen. Joseph F. Dunford, a Ranger School graduate and veteran infantryman, also is expected to have a leading role after taking over as the new chairman of the Joint Chiefs of Staff in October.

Today, about 220,000 positions are open only to men. Virtually all are in the Army and Marine Corps, including infantry and armor units that fight on the front lines.

Navy Capt. Jeff Davis, a Pentagon spokesman, said that the department has opened 111,000 positions to women since rescinding the gender ban last year and is poised to add thousands more jobs in the coming months.  Overall, women make up about 14 percent of the active-duty  military. The Marine Corps, which is 7 percent female, is the least integrated of the services and has been the most resistant to change.

The Army, Navy and Air Force are not expected to seek any exceptions to keep women out of combat jobs, the Associated Press reported Tuesday, citing officials who are aware of preliminary talks in the Pentagon.

Even the U.S. Special Operations Command is expected to allow women to compete for a broader array of jobs. If so, elite forces ranging from the Navy SEALs to the Army’s highly selective Delta Force could be open to women if they can meet the rigorous criteria to join those units.

Only the Marine Corps appears ready to resist the sweeping changes­ to gender roles, particularly in its infantry, where there is resentment of the idea from some leaders.

The Special Operations Command is also weighing changes to physical standards that could otherwise serve as a major barrier to female participation even if there is no longer a policy constraint. The review was launched to improve the process to select both men and women for the positions while reducing injuries, said Army Lt. Col. Robert Bockholt, a SOCOM spokesman.

The news is likely to be met with a mixed reaction among veterans and active-duty service members. “We understand that this will take time,” Bockholt said. “We want to get this right.”

The completion of the Ranger course by Griest and Haver was a particularly influential development, in part because of the stature associated with the Ranger name, a term whose history in America predates the Revolutionary War.

The Army has declined to identify the women so far, but The Washington Post was able to do so after observing Griest and Haver intermittently in Ranger School training in recent months. Both needed four months to complete the course, which includes parachuting, mountaineering, small-boat operations and patrolling at bases in Florida and Georgia.

Of 19 women who entered the training in April, only Griest and Haver have so far finished. A third female soldier remains in training, but the others have washed out.

Completing Ranger School, however, does not necessarily lead to assignments in the Ranger Regiment for its graduates. The school is considered the service’s premier leadership course and is attended by many service members each year who will never become part of the Ranger Regiment. Instead, they will serve in roles that include infantrymen, military police officers and helicopter pilots — returning to their units with a designation that helps them advance when under consideration for promotion.

The Ranger Regiment does not require all of its soldiers to attend Ranger School, but most eventually do. All leaders typically are required to before assuming their new positions of authority. The regiment also has its own training and assessment, including the difficult eight-week Ranger Assessment and Selection Program.

Barno said there has long been resistance to integrating the infantry, but he considers many of the objections to be based on flawed cultural arguments that men and women cannot coexist in a battlefield environment. They include concerns about privacy and mental toughness.

If “there is an argument beyond the physical requirements to be made, I haven’t heard it yet,” Barno said of integrating women. “They’ve shown they can do it.”

In part to test a broader transition in gender roles, the various branches of the military have opened training programs to women over the past couple of years and tracked the results.

The Marines opened up its Infantry Officer Course at Quantico, Va., well as its infantry training program at Camp Geiger, N.C. None of the 29 women who attempted the officer course passed, but about 44 percent of 240 female volunteers completed enlisted infantry training.

Craig Whitlock contributed to this report.