The Clinton campaign's decision to give up the server and a thumb drive containing backup copies of emails left Democrats scratching their heads as to why the former secretary of State had resisted for months turning over the server.

 Coupled with new polls that suggest Clinton is vulnerable, Democrats are nearing full-on panic mode.

"I'm not sure they completely understand the credibility they are losing, by the second," said one Democratic strategist, who spoke on the condition of anonymity. "At some point this goes from being something you can rationalize away to something that becomes political cancer. And we are getting pretty close to the cancer stage, because this is starting to get ridiculous."

 "Look, this is a classic example of the cover-up being 10 times worse than the so-called crime — though in this case there wasn't a crime," said another progressive strategist.

 "The culture of secrecy that has surrounded the Clintons — understandably, in some cases — has now yielded a situation where she did something that wasn't necessary and looks nefarious."