Hillary Clinton's email problem, long on the back-burner, boiled over again this week as two important and related developments turned up the heat.

Late Thursday, The New York Times reported that the inspectors general of the State Department and intelligence agencies are seeking a criminal investigation into the handling of "sensitive government information" on Hillary Clinton's private email server.

The reason emerged in a Friday report by The Wall Street Journal. Despite denying earlier this year that she sent any "classified documents" over email, the inspectors general found that Clinton had sent at least four emails containing classified information derived from the intelligence community. She did not, obviously, attach "classified documents" to her electronic messages, but she did send messages containing information that remains classified even to this day.

The four classified emails identified so far come from a sample of only 40 emails scrutinized by the intelligence agencies' inspector general from the 30,000 emails Clinton turned over to the State Department from her private server. The one in 10 ratio of emails improperly containing classified material would suggest the Democratic Party's frontrunner to become commander in chief sent as many as 3,000 emails containing classified information and then told falsehoods about it.

Even if there are nowhere near 3,000 such emails, it would be an extraordinary coincidence if the inspectors general just happened upon the only four such examples. In short, there are probably many more emails containing classified information improperly sent from Clinton's private server.

And because she destroyed another 32,000 emails before they could be turned over to the government — they weren't work related, trust her! — the amount of classified material put at risk by Clinton will probably never be known.

This calls Clinton's honesty into question yet again, and threatens her political future. But those are the least of the nation's problems. Far worse is that the foreign policy interests of the United States may have been harmed by her characteristic decision to put herself above the rules that apply to other people.

All government employees are required to preserve and turn over all emails in a timely fashion that are created or received through private channels. But national security concerns add hugely to the urgency of State Department pressure on employees not to use private email for work.

The transgression here is very serious — just as serious as the statement it makes about Clinton's character. With no justification more compelling than her own convenience, Clinton thwarted two key goals of federal law. First, she undermined the freedom of information for the public, as evidenced by the fact that her withholding of her work emails for years after they were created (and long after she left office) caused both public and congressional document requests to be improperly and incompletely fulfilled. Second, she undermined the national security interests inherent in keeping classified material secret.

Clinton and her supporters are as familiar with investigations as anyone in Washington. If the Justice Department gets involved, they can be counted on to claim persecution while vilifying everyone involved in figuring out how much damage she did. That's how the Clintons roll.

It's been said, perceptively, that Hillary Clinton avoids public outrage precisely because she has such a track record of high-handedness and cronyism. Arrogant rule-breaking is what everyone has come to expect from her and her family. But this transgression — or bungling — is sufficiently grave that it may stick in the long run, raising nagging questions of whether she is fit for the highest office in the land.