No one thinks she's going to be made to suffer formal legal penalties. She is obviously above the law. But there's law, and then there's bureaucracy. So a question for all of you keeping score at home: Will Hillary Clinton lose her security clearance?
Her clearance is doubtless inactive because she has been out of the government for a while, but it is doubtless a clearance of the highest level: TS/SCI, for Top Secret, Sensitive Compartmentalized Information. It happens that I know quite a bit about what is involved in obtaining and maintaining such a clearance. There is not a doubt in my mind that any normal person found to have passed classified information through their un-secure private email would be stripped of their clearance that afternoon, and would probably never be adjudicated eligible again.
There is no formal requirement that someone standing for President has to be eligible for a security clearance, of course. She will still be given access to anything at all in spite of being ineligible. Further, Mrs. Clinton is at the end of her public career: if she is not elected President, she will not serve in any other capacity.
Thus, there is no reason not to enforce standards in the usual way. Does anyone think that will happen?