Hillary Clinton’s Snapchat joke generated some laughs from her fans. However, the rest of the country was more puzzled than amused by the presidential candidate’s jest about preferring a service that automatically deletes messages. While campaigning in Iowa Clinton stuck to her position that the growing scandal about her emails was “pure politics.” That’s a line that is growing more untenable with each passing week as we learn more about her use of classified information on a private email server. Just today, it was revealed that the State Department has flagged more than 300 of the emails sent on Clinton’s personal account as possibly containing classified information. Considering that they’ve only gone through about 20 percent of the emails she released to the government (as opposed to the tens of thousands she deleted), that number is bound to grow. But though the shadow of this fiasco is looming over her campaign, right now she’s acting as if her real problem is Joe Biden rather than the prospect of being prosecuted for improper handling of secret material. Her awkward campaign style notwithstanding, it’s obvious that her camp believes acting confident in the face of disaster is the only way to ensure that Biden stays on the sidelines.

Though Bernie Sanders’ insurgent candidacy is drawing large crowds and gaining on Clinton in the polls, the Clinton camp still believes that, barring an unforeseen cataclysm, they can hold him off. Biden represents a different kind of threat. Sanders is attracting the Democrat’s liberal base, but no one in the party establishment thinks his boomlet is anything more than a protest movement, albeit a dangerously popular one. But Biden would offer the Democratic Party establishment, and in particular, the most ardent supporters of President Obama — especially African-Americas — a viable alternative to Clinton.

So it’s no surprise to learn that Clinton and the rest of her machine are working just as heard to lock up the Democratic donor base, as they are to hold off Sanders in Iowa and New Hampshire. As Politico reports, Clinton was working the party circuit in Martha’s Vineyard hard this past weekend trying to reassure her own backers as well as keep the president’s friends in line. Establishment Democrats are holding onto the hope that they can sweep to victory in 2016 on the basis of electing our first female president. They also still hope their nomination battle will not turn into an open brawl like the GOP race despite Clinton’s awkward and inauthentic efforts on the stump.

But the problem for Clinton is that the drip-drip-drip of scandal news is eating away at the core of her candidacy. Even her attempt to defuse the controversy with forced humor seems to have done more harm than good. Joking about being able to delete emails may have sounded like a good idea when the speech was written but as delivered it came across as another example of Hillary’s trademark arrogance.

If the State Department emails could be dumped in one batch onto the public square that would be to Clinton’s advantage. But her decision to hand over the emails in the form of 55,000 pages of material rather than as an electronic file means the process of unraveling the record will take many more months. That’s a tactic designed to make it hard to search the documents, something that fits with her overall strategy designed to thwart efforts to provide transparency. But it also gives critics more ammunition and drags out the process.

Clinton loyalists believe that she can survive this as long as the process doesn’t end in indictments, something that her wiping of her email server may make impossible. But the discovery of more classified emails, with many more likely to come, leaves her fate in the hands of the Department of Justice, rather than Democratic donors. It is still hard to imagine that the administration would permit such an outcome. But the possibility still exists that the steady accumulation of evidence that she did more than violate State Department rules will wind up with the former secretary of state and perhaps her aides being given the same draconian treatment that other officials (like former CIA director David Petraeus) have received. The lies and the reports about classified material are eating away at the public’s trust and her lead in the polls.

But right now, stopping Biden seems to be her priority. So long as the vice president isn’t lured into the race by Clinton’s problems, her camp seems to think they’ll be all right. Thus, Hillary’s false bravado about the emails and a strategy of denial aimed at convincing Democrats the danger of a criminal probe is about politics isn’t so much about her belief in her innocence. Rather it is a front designed to convince both Biden and potential Biden donors not to bother trying.

So far top Democrats haven’t felt forced to decide whether Clinton’s legal woes and her awkward campaign style renders her more of a liability than an advantage to her party. Clinton may also not fear facing the House Benghazi Committee because she believes that even the most damning admissions that are pried from Clinton and her staff by Rep. Trey Gowdy will be seen by Democrats as partisan warfare. The dead weight of the investigation and the revelations that what she has already said about the issue were lies is dragging her down in the polls. So long as she isn’t indicted, and Sanders remains her main opponent, Clinton probably thinks she’s still on track to be the Democratic nominee.

But even a successful effort to outmaneuver Biden shouldn’t be confused with a viable presidential campaign. If Clinton gets more bad news in the coming weeks about her emails or if it turns out the FBI is capable of resurrecting the material on the wiped server, all of the clever tactics she is employing against the vice president won’t matter much. Her donors may buy her bravado as well as her jokes, but it looks like most Americans are viewing her with the sort of skepticism that may doom her presidential ambitions.