But when the Senate derailed a sweeping bill to expand a host of post-military benefits two weeks later, on Feb. 27, Walsh saw how even an area that typically enjoys bipartisan support can crumble amid partisan acrimony. In addition to concerns over the package’s $21 billion cost, the legislation was defeated for an entirely unrelated reason: new penalties against Iran that Republicans sought.

WASHINGTON — When Senator John E. Walsh, an Iraq War veteran with 33 years of military service, was sworn into office last month, he expected that veterans’ issues could unite lawmakers, even in an atmosphere gripped by partisanship and gridlock.


“If more men and women in the US Congress would have served or had family members that served, that bill would have passed,” Walsh, a Montana Democrat, said in an interview. “They would have realized that we’re talking about veterans and their families.”

The number of veterans serving in Congress is at its lowest point in nearly 40 years, even as America winds down its military presence overseas. There are 18 senators and 83 representatives who are veterans, according to data compiled by the American Legion, a veterans advocacy group.

But the defeat of the veterans bill in the Senate was mostly a party-line vote, with all Republicans who are veterans opposing the measure. The divide signals another marker of the polarization that has plagued the chamber in recent years: The political affiliation of senators trumps their shared military bonds, even on legislation for veterans’ benefits that many people across the political spectrum say is needed.

The bill, which would have provided medical, job-training, and education benefits to veterans, failed to secure enough Republican support in a 56 to 41 procedural budget vote that fell mostly along party lines.

The low numbers of veterans in Congress stem mainly from the transition to an all-volunteer force in 1973, and veterans advocates said they see legislative impact in the shrinking numbers. They said that lawmakers with military backgrounds are uniquely positioned to speak about veterans and national defense issues.


“It brings experience to the table on issues we’re facing,” said Kate O’Gorman, political director at the Iraq and Afghanistan Veterans of America.

The clash over the bill, sponsored by Senator Bernie Sanders, a Vermont independent, reflects the stark and bitter divisions between the two major political parties. Only two Republicans, Senators Dean Heller of Nevada and Jerry Moran of Kansas, sided with Democrats to advance the legislation.

While Republicans and Democrats are usually quick to curry favor with nation’s 22 million veterans and their families, opposing Republicans raised objections over the bill’s funding mechanism, savings from military operations ending in Iraq and Afghanistan. They called that approach a budget gimmick, saying the money would not have been spent as the country’s military presence draws down.

“There a number of things that would be desirable in a perfect world, but we can’t afford all of them,” said Senator Roger Wicker, a Mississippi Republican who served in the Air Force and the Air Force Reserve.

Republicans further criticized language that would have opened up Department of Veterans Affairs facilities to veterans without service-connected injuries, which they said would worsen wait times at clinics and the backlog of disability claims.

“It would make a system that’s having a hard time functioning collapse,” said Senator Lindsey Graham,a South Carolina Republican who is in the Air Force Reserve.


Republicans demanded the opportunity to offer amendments, including a less expensive plan proposed by Senator Richard Burr, a Republican from North Carolina, that would not have opened VA facilities to those with non-service related disabilities.

In addition, it would have imposed new sanctions on Iran for its nuclear program, an issue that has split some Democrats and the White House.

“The Republicans saw an opportunity to maybe cause a division between Democrats and politically embarrass the president,” Sanders said in an interview.

Last January, Sanders became chairman of the Senate Veterans’ Affairs Committee, but his path to the position, in many ways, was unlikely. Sanders has maintained an antiwar stance since he first ran for Congress in 1971 and voted against going to war in Iraq in 2002.

But Sanders said taking care of the men and women hurt in military conflicts is Congress’s obligation.

At one point in the 1970s, roughly four out of five members of Congress were veterans, mostly of World War II, according to the American Legion. Democratic Senator Edward J. Markey of Massachusetts, who served in the Army Reserve in the Vietnam War, is the only member of the state’s delegation with military experience.

When John Dingell, the Michigan Democrat, announced last month that he would retire at the end of this year’s term, it meant that Congress will lose one of its only two World War II veterans.

“The veterans are going to be largely dependent on the members of Congress who are civilians,” Dingell said in an interview.


Lawmakers who served with more veterans say their shared military backgrounds fostered greater collaboration.

“We had good, strong voting power,” said the former senator John Warner, a Virginia Republican, World War II and Korean War veteran, and former chairman of the Armed Services Committee.

In a Congress stymied by gridlock, deal-making is much harder to achieve, even on a bill that Sanders emphasized has broad bipartisan support. Burr, for one, has said his competing proposal incorporates 80 percent of Sanders’s legislation.

For Sanders to move his bill forward, he must secure three Republican votes. Walsh said lawmakers have paid a lot of “lip service” when it comes to veterans’ issues — but do not necessarily take action.

“We’re taking about the lives of the men and women who have sacrificed so much for our country,” he said.

Kimberly Railey can be reached at kimberly.railey

@globe.com.