This is the legally sound -- and politically conservative -- position.
The handling of sensitive information is a serious matter, in an understatement. If it isn't a serious matter, perhaps the government ought not to be handling it.
If you have been alarmed by the decades long march towards overcriminalization and overregulation along with the gradual erosion of the mens rea (criminal intent) requirement for criminal culpability, today's statements reflect a reaffirmation of several positive core values in the classic American jurisprudence as it pertains to criminal law. It is a victory for due process, for the liberty-protecting and government-power-restraining principle that one is presumed innocent until proven guilty in a court of law, and a victory for erring on the side of letting a guilty person go free over risking the liberty of the innocent. It is a victory for reason, over the passions of the street mob.
First, we see restraint in the use of government power. Haven't we seen far too many politically-driven or politically-suspect investigations and prosecutions in recent years? We should be thankful that we have a recognition of the value of restraint, whether you agree with the outcome and its political (for the moment) impacts. We should appreciate any time when the government acknowledges the ferocity of its fearsome prosecutorial powers and yet steps back -- and particularly when such power could rightfully be accused by a significant portion of the populace to either be politically driven or risking tipping the balance of a presidential election. (Note: It is useful to note that while the FBI and Justice Department work hand in hand and often effectively in tandem, the FBI's function is investigative and the Justice Department's function is prosecutorial, although one can be sure the FBI's recommendations carry great weight.)
Second, bad judgment is not a crime and neither is negligence. Director Comey criticized Clinton for being "extremely careless" but that is not a crime. The risks to the liberty of average Americans will be immense once we dispense with the criminal intent requirement. We don't prosecute people for mistakes -- not like Italy which started prosecuting geologists for failing to predict an earthquake in the last decade. That is a crucial point. Reasonable people can and do disagree on what is sound judgment, sound policy and so on.
We risk a great deal by rushing to criminalize policy differences and particularly when they are embodied by political opponents. This is most true, in a day when anti-intellectualism is on the march, when ignorance is celebrated and achievement often considered something that makes its holder suspect, when the Internet has emboldened the uninformed to delude themselves into believing and asserting that they are experts instead of fools.
Realize one point: these people, unaware of their foolishness, serve on juries!
But the prosecution of political enemies for subjective decisions should be the province of banana republics which pay lip service to sue process. Not of America.
Director Comey's remarks acknowledged bad judgment. And the judgment may even rise to egregious levels. You could even question whether such judgment warrants a candidate's disqualification (in the minds of voters), but that is a matter to be decided by voters and not by bureaucrats. Again, this is the federalist, restrained-government-power position.
The third and final point derives from the second. There are in some quarters the demand for a prosecution of Hillary based on who she is, what her role was. Again, this runs counter to the American legal tradition. We prosecute the act, not the man, nor the title.
When we start prosecuting people because of what they are, because they are business owners or elected officials and not really because of what they have allegedly done, we are again in despot territory where power exists to be abused and where men live at the mercy of the State.
Prosecuting Hillary because of her status, her achievements, is thusly wrong. Similarly, going after her in order to prove that "no one is above the law" also acts as a powerful and dangerous precedent, one which would surely embolden future reprisals and even more venal abuses of power.
Finally, the approaching election is and should be decided by the voters with as little government interference as possible. This again is the classic federalist position arising from the Bill of Rights and the enumerated powers of our Constitution, a document which stands for the limits of government power and the principle that the people must be protected from government overreach.
Yesterday we celebrated our independence. Lest we forget, the War for Independence began as the culmination of years if not decades of colonists' frustration with arbitrary and abusive government acts committed in the name of the Crown (the Kings of England).
So today's FBI decision should be hailed. Detractors may decry the perceived absolution of Hillary Clinton. But future Americans will be freer with this important Executive Branch decision affirming the value of the restraint of the State's prosecutorial power.