The Obama administration is not ignoring this threat. Last month a bold raid by U.S. Special Forces killed one of Somalia's top al-Qaeda operatives. But such stand-off counterterrorism operations are no more likely to solve the problem on their own than they are in Afghanistan and Pakistan. What's needed is a complementary and concerted effort to bolster the Somali government and its army, so that it is able to turn back al-Shabab and extend its authority across the country.

Secretary of State Hillary Rodham Clinton recently met President Sharif Ahmed and said that his moderate Islamist administration was "the best hope we've had in quite some time for a return to stability." But U.S. support for Mr. Ahmed has been modest. Washington is a big donor of food and other humanitarian aid and provides funds to train the military, but Mr. Ahmed recently told The Post that he desperately needs more military support and an expansion of a U.N. peacekeeping force.

Administration officials say that a review of the situation in Somalia is underway, with aims that include strengthening the government. It's a hard problem: The country has lacked a national government for 20 years, and attempts by the past three U.S. presidents to help restore order, with U.S. troops or with proxies, failed dismally. But Somalia is not a country the United States and its allies can ignore or treat merely with missile strikes. As in Afghanistan before 2001, the mounting threat of terrorist organizations, and their potential to strike far beyond the horn of Africa, are apparent. The indelible lesson of Sept. 11, 2001, is that they must be countered aggressively.