Veterans Affairs Secretary Eric Shinseki has faced tough battles before.
He's a twice-wounded Army veteran of the Vietnam War and was a harsh critic of George W. Bush's strategy for the invasion of Iraq.
But whether Shinseki, who is one of President Obama's longest-serving Cabinet secretaries, can emerge from the crisis over veteran deaths and other problems at VA facilities remains uncertain.
Shinseki is scheduled to testify Thursday before a Senate committee as lawmakers, mainly Republicans, along with the head of the American Legion, are calling for the former general's resignation.
The White House and top Democrats have said they remain confident in Shinseki, whose agency faces enormous challenges providing for the vets returning from the overseas wars in Iraq and Afghanistan. While the overall number of vets has declined since the 1980s, younger veterans and those with disabilities are on a steep rise.
Shinseki's leadership has come under fire after claims that up to 40 veterans' deaths have been linked to excessive wait times for service at a Phoenix VA facility, where officials may have kept separate record books to hide the problem.
Whistle-blowers in other states have raised similar concerns of long waits and other problems with VA care, including in Mississippi, Missouri and Texas.
"We still don't know exactly how many veterans have died or otherwise suffered because of the VA's assorted failures and abuses, but we do know that it's disgraceful," said Sen. John Cornyn (R-Texas), who has called for Shinseki to resign, on the Senate floor Wednesday.
Rep. Jeff Miller (R-Fla.), the chairman of the House Veterans Affairs Committee who first disclosed the possible links between wait times and the Phoenix deaths, has subpoenaed all emails and correspondence between VA officials in Phoenix and Washington, including Shinseki. He has not called for the secretary's resignation resign pending an inspector general investigation.
But Miller asked Obama this week to form an independent, bipartisan commission to investigate the reports that are surfacing on a "near-daily basis," and he expressed "grave" concerns over whether the VA could adequately conduct an internal review.
Shinseki will face the Senate Veterans Affairs Committee, which has long investigated problems at the VA. And even though the strongest criticisms of Shinseki have come this election year from Republicans, Sen. Bernie Sanders, the independent from Vermont who votes with Democrats, said in announcing the hearing: "The VA has got to do better."
Shinseki placed three Phoenix officials on administrative leave earlier this month, including the center's director and associate director, but has otherwise sought to allow the inspector general's investigation to proceed before taking further action.
The nation's veterans' service organizations will also testify at Thursday's hearing, but even those who have refrained from calling for Shinseki's resignation expressed little tolerance for ongoing problems.
The Iraq and Afghanistan Veterans of America, which is surveying its members on whether to back Shinseki, said it is long past time for Obama to make "bold" reforms at the VA.