text: The author didn't mention it but tit-for-tat works best where the opponent gains little from the bullying, while you gain a lot by ending it.  That's true in games and trade.
  
  Take a bear survival analogy.  If you come face to face with a bear, stay still (co-operate).  If it is alone, and makes for you, ready to fight (retaliate).  Yell.  Throw your backpack. Pull your knife.  Grab a branch and fight.  Running makes you look like food, and belligerence makes you look like a difficult meal.  But Trump is definitely not starving.
  
  However, if the bear is with cub this probably won't work. She has more skin in that game and belligerence just makes you look like a bigger threat.  Putting distance between you and the cub is your top survival priority.   We are not a security threat to the US.