Look at it this way. If we don’t do anything about this, it could really undermine our credibility among the Iraqis. It could certainly be spun into the argument that we’re perfectly willing to beat up on Iraqis, but won’t lift a finger to protect Iraq’s borders and resources from foreign enemies.
That could be a motive for this move. Iran senses that we lack the political will to do anything, so they’re calculating that they’ll be able to weaken us politically in Iraq, which can only work to their benefit.
That's very good insight. Makes sense to me. The incident *seems* to be over but it sure gives a lot to think about.