This last week’s news has got me thinking about the particularities of the formulation of US foreign policy – and how it is important that our friends, allies, and even rivals understand why we do the things we do.

An extremely important part of understanding other countries’ foreign policies is to understand how their political systems work. You would be hard-pressed to grasp the comings and goings in Germany, Lebanon, and China if you didn’t understand German coalition politics, Lebanese confessionalism, and modern Chinese communism. By the same token, US allies and rivals, many of whom use simple majority parliamentary systems, can’t possibly understand American foreign policy unless they are proficient in our political system, namely the enormous influence that individual legislators, even in the minority party, exercise over foreign policy decisions.

The filibuster, seemingly the most ridiculous...