Ronny L. Jackson’s imperiled nomination to lead the Department of Veterans Affairs underscores the agency’s deep-seated struggle to overcome years of scandal and return its focus to serving a constituency that, historically, has remained above the political fray.

“This is complete and total chaos after years of complete and total chaos,” said Paul Rieckhoff, founder and chief executive of Iraq and Afghanistan Veterans of America, an advocacy group. “Our veterans deserve so much better. Our whole country does. Especially in a time of war.”

Jackson, a one-star Navy admiral serving as President Trump’s physician, has been accused of improperly dispensing medication and maintaining a hostile work environment while overseeing the White House medical staff. He has denied any wrongdoing. Senate lawmakers have postponed his confirmation hearing while they determine whether the allegations have merit.

For the 9 million military veterans who rely on VA for medical care, vocational training, home loans and burial services, the uncertainty is “distressing,” said Garry Augustine, who heads the Washington headquarters of Disabled American Veterans. DAV was among the advocacy groups whose representatives met Tuesday with 60 regional hospital directors and administrators at a conference center in Potomac, Md., for a panel discussion about improving VA — from streamlining its hiring process for doctors and mental-health professionals, to cutting the time it takes to make appointments and process benefits claims.

Augustine credited VA’s career employees for trying to remain focused amid the turmoil, but he described the mood among conference attendees as “numb.”

Hanging in the balance is proposed legislation — the Caring for Our Veterans Act — that would expand veterans’ access to health care. Known as the Choice program, it allows patients to seek medical services from private providers at taxpayer expense. The bill was left out of the federal budget that passed last month after Democrats raised concerns that the measure would mark a first step toward dismantling VA.

Now, funding for the Choice program is set to run out next month, and lawmakers are scrambling to push through a compromise plan.

VA once was regarded as one of the federal government’s most successful agencies, propelling the post-World War II generation into the middle class through education benefits provided by the Montgomery G.I. Bill and conducting groundbreaking research in the areas of spinal reconstruction and rehabilitation for amputees. But the agency, which employs more than 360,000, has been in a state of decline since at least 2014, when revelations surfaced that employees at some VA facilities had falsified records about the amount of time veterans waited for often urgent mental and health care.

Trump, who during the presidential campaign characterized VA as “the most corrupt agency in the United States,” pledged to fix the department. Through his first VA secretary, David Shulkin, the administration saw some early success, opening an office that protects whistleblowers, making it easier to fire underperforming employees and beginning to modernize the benefits-appeals process.

But in recent months, the agency has become a poster child for dysfunction again. Shulkin’s firing in late March was brought on, in part, by his public battles with other political appointees within VA and the White House.

VA’s acting secretary is Robert Wilkie, who moved into the role from an appointed position at the Defense Department. Since he began at the agency, he has implored its workforce to remember VA’s sacred mission of caring for those who have fought the nation’s wars. Given the questions facing Jackson’s nomination, some surmise Wilkie will be in the job awhile.

Yet what has been lost amid the political disputes, veterans’ advocates say, are VA’s most vulnerable clientele, men and women who have suffered catastrophic combat wounds or are battling severe mental-health setbacks because of post-traumatic stress. Others simply want the peace of mind knowing they won’t encounter trouble accessing their education benefits.

The VA also helps homeless veterans find housing and rehab. It has a suicide prevention hotline, which among many other programs, is trying to help stop astronomically high rates — 20 per day — of veterans who take their own lives.

“Veterans are losing six different ways right now, from all directions,” said Joe Chenelly, the national executive director of AMVETS. “What makes it stop?”