DANIEL HENNINGER: Suddenly, A Credibility Gap: Benghazi has damaged voters’ willingness to believe in Barack Obama. “In time it was no surprise that people began to ask: Was the White House hiding something about an event of enormous gravity to protect the president’s candidacy? For much of the American electorate, that would be cause to start marking down a presidency.”

UPDATE: Obama takes ‘offense’ on some Benghazi accusations. In other words, he’s now on the defensive.