Benghazi is an impeachable offense
The charge of high crimes and misdemeanors covers allegations of misconduct peculiar to officials, such as perjury of oath, abuse of authority, bribery, intimidation, misuse of assets, failure to supervise, dereliction of duty.
"High" in the legal and common parlance of the 17th and 18th centuries of "high crimes" signifies activity by or against those who have special duties acquired by taking an oath of office that are not shared with common persons. A high crime is one that can only be done by someone in a unique position of authority, which is political in character, who does things to circumvent justice. The phrase "high crimes and misdemeanors" when used together was a common phrase at the time the U.S. Constitution was written and did not mean any stringent or difficult criteria for determining guilt. It meant the opposite. The phrase was historically used to cover a very broad range of crimes.
The Benghazi cover-up would fit the definition of a high crime and is therefore, an impeachable offense.
The Constitution defines the criteria for impeachment: "The President, Vice President and all civil Officers of the United States, shall be removed from office on Impeachment for, and Conviction of, Treason, Bribery or other High crimes and Misdemeanors."
With a tight election right around the corner, the Obama administration chose to explain the Benghazi terrorist attack as a spontaneous uprising caused by a YouTube video. White House talking points were revised 12 times in the several days following the attacks. It was perceived by the Obama administration that the truth would have cost votes. After all, al-Qaida was dead, right?
At this point, I think impeachment would be a mistake. We need to undo the damage of the last five years like repealing Obamacare. An impeachment would be a Pyrrhic victory.