It’s among the more curious recent coincidences in Congress. The veterans’ health care scandal reached a climax, and galvanized unusually bipartisan outrage — just as the dwindling roster of veterans slips below a symbolic threshold.  

The defeat of 91-year-old Rep. Ralph M. Hall in the Texas Republican primary last week means there won’t be any veterans of World War II at the Capitol come January. He was among the nearly 500 members from the “greatest generation” who served both during the war and in Congress.  

Hall’s impending departure underscores how the decline in members with military experience has been accelerating for three decades, creating ample anxiety for veterans organizations. As their roster of virtually guaranteed Hill allies has dwindled — and splintered among lawmakers who served in half a dozen conflicts — these groups have grown increasingly concerned that Congress is losing its ardor for forcefully addressing veterans’ concerns.  

Their fears have grown as budget constraints have intensified and because the House and Senate Veterans Affairs committees have gained reputations as legislative backwaters — not only beset by rapid turnover, from the top seats on down, but also now infused with the partisanship that had for so long skirted these committees.  

The worries will be tested anew this summer, no matter who is nominated to run the Department of Veterans’ Affairs to replace Eric Shinseki, who resigned last week . Revelations about astonishingly long waiting times for appointments at VA hospitals and clinics, and efforts by officials to cover up the problem, is applying considerable pressure on both parties to compromise on legislation smoothing delivery of care to the 6.5 million veterans who use the system annually.  

Senate Democrats on Sunday unveiled a revived and expanded version of their comprehensive VA health care bill , which was blocked by a GOP filibuster in February. It calls for overhauling the VA appointment scheduling computer system, hiring more medical personnel, making it easier to fire senior department officials and creating 27 new veterans clinics. Implementation would cost at least $18 billion during the next five years.  

When the House returns next week, it will begin moving legislation embodying the GOP’s big idea on the subject, which is to make the VA embrace more privatization. The bill would permit any veteran who has waited more than a month for an appointment at a department facility to get care from a private hospital or doctor, with the VA providing vouchers for footing the bill.  

Both measures look likely to move through the Veterans’ Affairs committees, creating rare moments in the national spotlight for a pair of panels that are more often regarded as legislative afterthoughts by leadership and as way stations by the rank and file.  

In the past decade, the chairmanship of the Senate panel has changed five times and the House committee gavel has been passed along four times. Six of the 14 seats on the Senate committee have changed hands over the last four years. Turnover on the House side has been even more dramatic: Nine of today’s 14 Republicans, and eight of the 11 Democrats, are in their first or second terms. That’s 17 of 25 lawmakers who are relatively new to Congress. The general rule has been that members are willing to bide their time on the VA panels only until their bids come through for more powerful or prestigious committee posts.  

In the winter, Republicans blocked the Senate bill to protest both its cost and the restrictions imposed on what amendments they could offer. Now, with the wait time scandal on the front pages, Democrats are betting a sufficient number of Republicans will reverse course.  

GOP interest in more private care, and the thwarting of the Senate bill, have caused friction between veterans lobbying groups and the top Republican on the Senate panel, Richard M. Burr of North Carolina. (Another sign of the high turnover on the panels is that Burr rose to be ranking member after just four years as a senator.)  

The rift burst open over Memorial Day weekend, when Burr offered a blanket condemnation of veterans organizations , saying they are “more interested in their own livelihoods and Washington connections than they are to the needs of their own members.” Many of the groups lambasted him right back, with several of Burr’s critics suggesting he had no feel for the real concerns of people who wore a uniform because he is not among them.  

Sticking by that correlation could prove problematic for the veterans groups. Military service is on the resumes of only eight of the 39 lawmakers now serving on either of the VA panels — and none of them is a chairman or ranking member.  

Those numbers are a precise reflection of the entire 113th Congress. Just 19 percent of the current membership served in the military (86 lawmakers in the House and 18 in the Senate). That percentage peaked at 77 percent (347 in the House and 65 in the Senate) in 1977, when members of the World War II generation were in their late 40s and early 50s. With those people aging and the era of an all-volunteer armed forces set in place, the share of veterans has been shrinking since — dropping below half of lawmakers in the middle 1990s and falling below one-quarter a decade ago.  

According to data compiled by CQ Roll Call, nearly one-third of the veterans now on the Hill served during the Iraq or Afghanistan wars. Only a dozen House members and one senator, recently appointed Democrat John Walsh of Montana, saw combat.  

Speaker John A. Boehner is the only member of the leadership with any military service. He enlisted right after graduating from high school in Ohio in 1968, at the height of the Vietnam War, but was honorably discharged after eight weeks in the Navy because of a back problem.  

The 2012 election, meanwhile, was the first presidential contest since 1944 when neither major party nominee was a veteran.  

Hall, first elected in 1980, will now join Democratic Rep. John D. Dingell of Michigan, who’s retiring, in turning out the lights on the Hill’s World War II generation in December. (The Senate’s final veteran of that conflict, Democrat Frank R. Lautenberg of New Jersey, died last year.)  

The first of their ilk arrived in 1944, before the war was even over. That’s when Democrat George Andrews won an Alabama House seat while on active duty in the Navy, and Republican William Jenner was appointed to fill a Senate vacancy fresh from his discharge as a captain in the Army Air Corps.  

Jenner retired in 1958, while Andrews stayed until 1970. But neither of them ever served on a committee that handled veterans policy. In their day, there just weren’t enough seats to go around.