I watched the debates from a lively Brooklyn bar where a crowd of locals listened intently as Obama and Romney listed countries that they might bomb or already have. They threw jabs at China and Romney said he loves teachers and hates food stamps for good measure, but for the most part, the candidates had a myopic conversation about foreign policy that predictably drew artificial lines around what is foreign and what is domestic.

It should have come as no surprise that war making and security threats made up the bulk of last nights debates. As Ezra Klein wrote yesterday, arguing that the domestic/foreign policy divide fails to recognize that our national problems can’t be solved in isolation:

>Washington’s definitions of “domestic policy” and “foreign policy” haven’t kept up with the real world. When you hear the term “domestic policy” in the Beltway, it means economic policy, health-care reform, financial regulation, energy. “Foreign policy” means, broadly speaking, our policy towards the countries we are already at war with, or are considered likely to eventually go to war with. But the actual policies don’t break down so neatly.

Think, for example, of immigration. Nary a word was given on the subject. Properly understood, immigration is a foreign policy issues as much as it is a domestic or social one. Global migration is tied directly to US-supported, global free-trade policies that propel millions to leave Mexico and Central America for the United States. But this went unmentioned, aside from one sentence from Romney, promising to “increase” trade with Latin America.

Nor was there mention of the raging drug war south of the border that’s left tens of thousands dead and continues to drive migration.

Immigration is not a sufficiently important foreign policy issues because the U.S. has declared no wars in Latin America. But because our domestic policy discussions stop at our borders, substantive discussion of migration beyond who we will and will not deport was similarly excluded from earlier debates.

These are not just rhetorical omissions. The failure to recognize that our most fraught domestic issues are tied to global politics and economics, helps make those issues intractable.

The foreign and domestic policy debate structure may be about as antiquated as those bayonets Romney got zinged with last night.