If I had to evaluate the quality of argument in the presidential debates with one word, it’s “simplistic.” But the level of simple-mindedness varies by topic.

For foreign policy, at least, candidates often propose a policy, consider how other nations might respond, and suggest a counter-response. For example, here’s Richardson on Darfur:

Number one, more U.N. peacekeepers. The government is refusing to make this happen.

Secondly, economic sanctions. We’ve imposed them, but they’re weak. We need European countries to make them happen.

Third, we need China, to lean on China, which has enormous leverage over Darfur. And if the Chinese don’t want to do this, we say to them, maybe we won’t go to the Olympics.

It’s still simplistic, but at least Richardson thinks about U.S. strategy, other countries’ response to the U.S. strategy, and the U.S. response to their response. When they talk foreign policy, candidates in both parties often rise to this level.

On domestic policy – which usually means economic policy – it’s a different story. On these questions, candidates usually describe their intentions, propose a policy, and “infer” that the policy will achieve those intentions. The only strategic issue: Will our opponents spend money to prevent the policy from happening? They virtually never ask: How will people actually respond to our policy, if implemented? Take Obama on health care:

My belief is that most families want health care but they can’t afford it. And so my emphasis is on driving down the costs, taking on the insurance companies, making sure that they are limited in the ability to extract profits and deny coverage; that we make sure the drug companies have to do what’s right by their patients instead of simply hording their profits.

If we do those things, then I believe that we can drive down the costs for families.

Gee, is it possible that insurance companies and drug companies might change their behavior if you limit their ability to “extract profits and deny coverage” and “make sure” they “do what’s right by their patients instead of simply hoarding their profits”? That kind of question isn’t on the agenda of either party.

Why would there be this asymmetry between foreign and domestic policy? My wife suggested a hypothesis that rings true to me: It’s hard to avoid strategic thinking for foreign policy because you’re doing things to people who aren’t “under your jurisdiction.” With domestic policy, in contrast, government is telling “its own people” what to do.

Even the truly naive realize that if the U.S. passes a law saying that Iranians can’t do something, it might blow up in our face. But if the U.S. passes a law saying that American drug companies can’t do something, the truly naive think they’ve solved their problem.

And of course, if you’re trying to win votes in a presidential primary, the truly naive are your target audience.