SECRETARY WITHOUT HONOR: When I hear people say Clinton emails don’t matter, I remember a young Marine captain who owned up to his career-ruining mistake.

Apologists for Hillary Clinton’s alleged criminal mishandling of classified documents say that it doesn’t matter, that she really did nothing wrong, or nothing significant. But the real question is not so much what she did as how she has responded to being found out.

Once during the mid-1960s when I was on active duty in the Marine Corps, I was the air liaison officer for a battalion of Marines aboard 11 ships in the Mediterranean. As the air officer and a senior captain, I had a rotating responsibility for the nuclear codebook, kept in the safe in the operations room of the lead amphibious squadron command ship. I shared that duty with another captain, a squared-away young man, liked by all he commanded and the son of a very high-ranking Marine. . . .

Against all regulations, the codebook had been out of the safe and unattended. It mattered not that it was unattended for only seconds, that the ship was five miles at sea or that it was certain no one unauthorized had seen the code. The captain could have explained this to the operations sergeant. He could have told the sergeant that he “would take care of it.” He could have hinted that his high ranking dad could smooth it over.

But the Marine Corps’ values are honor, courage and commitment. Honor is the bedrock of our character. The young captain could not ask the sergeant to betray his duty to report the infraction, no matter how small. Instead, the captain simply said, “Let’s go see the colonel.”

That captain had wanted to be a Marine officer all of his life. It was the only career he ever wanted. When he reported the incident to the colonel, he knew he was jeopardizing his life’s dream. But he did it.

The results went by the book. The amphibious squadron stood down. Military couriers flew in from NATO. The codes were changed all over Europe. The battalion was a day late in leaving the Mediterranean. The captain, Leonard F. Chapman III, received a letter of reprimand, damaging his career. He stayed in the corps and died in a tragic accident aboard another ship.

I saw some heroic acts in combat in Vietnam, things that made me proud to be an American and a Marine. But that young captain stood for what makes our corps and our country great. . . .

Hillary Clinton is the antithesis of that young captain, someone with no honor, little courage and commitment only to her endless ambition. This has nothing to do with gender, party affiliation, ideology or policy. It is a question of character — not just hers, but ours. Electing Clinton would mean abandoning holding people accountable for grievous errors of integrity and responsibility. What we already know about her security infractions should disqualify her for any government position that deals in information critical to mission success, domestic or foreign. But beyond that, her responses to being found out — dismissing its importance, claiming ignorance, blaming others — indict her beyond anything the investigation can reveal. Those elements reveal her character. And the saddest thing is that so many in America seem not to care.

We have the worst political class in America’s history. That is not entirely an accident.