Charges against one of the Marines, Lt. Col Chessani were thrown out because the court found the appearance of undue command influence by General Mattis.
Marine Cleared In Haditha Massacre
A military judge dismissed charges Tuesday against a Marine officer accused of failing to investigate the killings of 24 Iraqis.
Col. Steven Folsom dismissed charges against Lt. Col. Jeffrey Chessani after finding that a four-star general overseeing the case was improperly influenced by an investigator [General Mattis]
probing the November 2005 shootings by a Marine squad in Haditha.
"Unlawful command influence is the mortal enemy of military justice," Folsom said.
So, yes, General Mattis has his flaws.