No,it is not
The principal "offenses" at Benghazi were the failure to rescue Ambassador Stevens and the failure to provide fire support to Doherty and Woods.
There is absolutely no question that the decision to commit or to withhold US forces from urban combat in a foreign country is within the authority of the Commander in Chief. His decision in this regard was a legal exercise of his Constitutional authority and could not under any circumstances be a crime.
Of course, the wisdom and propriety of his actions was a completely legitimate subject for the electorate, but unfortunately his opponent in the 2012 election chose not to make an issue of it.
That's it. It's over.