Here's my op-ed that uses long-term orientation, probabilistic thinking, numeracy, consider the alternative, reaching our actual goals, avoiding intuitive emotional reactions and attention bias, and other rationality techniques to suggest more rational responses to the Paris attacks and the ISIS threat. It's published in the Sunday edition of The Plain Dealer, a major newspaper (16th in the US). This is part of my broader project, Intentional Insights, of conveying rational thinking, including about politics, to a broad audience to raise the sanity waterline.
If the Mongols are running away in panic you should pursue since pursuers normally have a big advantage, if they are running away as part of planned strategy you should not.
What you should or should not do is better determined by whether or not it helps win the war than whether it helps win a battle. If pursuing causes your unit to leave the territory you should have been defending, the mere accident of another of their units stumbling across the undefended territory could lose you the war, without any planned strategy on their part.
It is insufficient to know their plans. You have to know your own.