Democrats who believe they have emerged unscathed from the Republican focus on Benghazi and the IRS—which President Obama has described as a "sideshow"—are not quite as confident about the burgeoning scandal at the Veterans Administration. As Congress opens hearings on allegations of secret "waiting lists" and veterans dying because of treatment delays, the political threat is considered very real.

"The one that I think hurts the Democrats the most is not Benghazi, is not IRS, is not Obamacare," said veteran Ohio Democratic strategist Jerry Austin. "It is the Veterans Administration. The idea of having wounded warriors dying and all these terrible stories here, that is something that no one can defend."

He added, "It looks like that is one that has legs."

Longtime Republican strategist Rich Galen sees the same thing. "Benghazi and IRS, those are things that have the coastal press rolling their eyes," he said. "But this VA thing is huge. If I were the Republican Conference, I would give up everything else and just throw both feet into the VA."

As Austin suggested, Democrats are not rushing onto television to defend either the VA or the administration's handling of veteran claims. One of the few senators willing to do so has been Bernie Sanders, the Vermont independent. And it didn't go particularly well for him when he was interviewed Thursday morning on CNN's New Day.

When he suggested that some of the veterans who died waiting for treatment at an Arizona facility may have died from causes unrelated to the delay in their treatment, he was immediately attacked. CNN's Chris Cuomo, in a withering response, told Sanders: "You sound like a lawyer defending the hospital, as opposed to a senator trying to make sure the right thing is done." Thrown on the defensive, Sanders never recovered, rather meekly suggesting, "We know that people die every day. We don't know why they die."

Not many Democrats are going to make that kind of defense of the VA. Instead, the White House is braced for bipartisan criticism even as it cautions patience while the allegations are investigated. To show his commitment to fixing the system, the president has already dispatched one of his most trusted advisers, Deputy Chief of Staff Rob Nabors, to oversee the VA investigation.

But Republicans are not satisfied with the administration response. Republican National Committee Chairman Reince Priebus has demanded an independent investigation. "Our veterans are our heroes and they deserve better than a White House insider-led investigation," Priebus said in a statement. "They deserve an independent investigation. Yet again the White House is trying to pass off a scandal as an isolated incident when in fact it continues to grow every day."

Press secretary Jay Carney, who fielded some tough questions on the topic Wednesday, on Thursday cast the president as outraged by the stories of VA delays. "He certainly is concerned and angry about the allegations we've seen" in the Phoenix office, Carney told reporters aboard Air Force One on the return flight from New York. If they are true, he added, "that would be outrageous."

The political peril for the president comes from more than just the absence of Democratic defenders, the bipartisan nature of the outrage, and the widespread anger at mistreatment of veterans. It also threatens to once again raise questions about the competence of the administration to run the government after the botched rollout of the Obamacare website, questions the administration believes it has finally quieted.

The VA issue is also likely to revive accusations that Obama does not demand accountability in his government. As he did when there were demands that he fire Health and Human Services Secretary Kathleen Sebelius over the Obamacare website issues, the president is now resisting calls to fire VA Secretary Eric Shinseki.

Both issues contribute to the president's overall approval ratings, which have recently shown signs of inching above the low 40s. Democrats do not expect them to rise as high as 50 percent before the November election, but believe if they can hit 46 percent it can make a difference in several races.