Trade can be weaponised as a coercive tool of policy, either to force another government to change course or to change its internal calculus when making choices. That last part is useful to bear in mind: government decisions are the result of an equation with many variables. When we dismiss the leaders of unfriendly regimes as erratic or insane, we’re often simply misunderstanding the variables their decision-making equation contains, or the weights they are attaching to them.