The hubbub a while back about Mexico being a failed state was premature at best, but the problem of how to respond to disorder and violence in Mexico isn’t going away. That’s why it’s worth looking at a new series by Glynn Custred entitled “Alternatives for the U.S. Should Mexico Face the ‘Worst Case Scenario’.” (It’s in five parts: one, two, three, four, and five.) He goes over in detail the challenges facing Mexico and our possible responses under international law. Most controversial would be direct military intervention, which he contends today’s circumstances already justify, though he doesn’t call for it and would clearly prefer to avoid it:

Most relevant are those incidents in which American armed forces were deployed on foreign soil not pursuant to treaties made between the two countries, but rather to suppress banditry, piracy and the slave trade, or to protect American lives, property and diplomatic missions, or in retaliation for depredations on American citizens and American interests. Such grounds for intervention are covered by the peremptory norms of customary law.
Peremptory norms have not been specifically enumerated and catalogued by any authoritative body, but they include the protection of a country’s citizens abroad, its property and agents when there is no government able to perform its functions, as well as suppressing such universally condemned violations as piracy and slavery. In the case of the failure of the Mexican state to maintain law and order in its territory, to the point where those norms are violated, the United States has the right to intervene militarily under established international law backed by precedence. The United States has already has the right to intervene militarily in Mexico under Article 51 of the United Nations Charter in response to the numerous deliberate incursions by units of the Mexican army and police into the United States. If conditions should worsen, that record of violations would bolster an already sound case for a U.S. military response.

Be warned that the whole thing is quite long. But if you have any interest our nation’s chief security challenge — one far more important than the fate of goat-herders in the Hindu Kush — then you’ll want to read it.