He wants to damage Trump on his way out the door. Democrats are all the same, it’s all about party, not country. Mattis knew Trumps philosophy when he took the job. He could have left with dignity and appreciation for being chosen for such a critical and honored position. But now he wants to throw a grande on his way out. That makes him a POS in my book.
Have to really agree with your statement that he knew all of Trump’s attitudes toward the allies when he took the job. That is a very strong point against his letter.