The anniversary of Osama bin Laden’s death last week focused attention briefly on the continued threat posed by al Qaeda Central. But what about al Qaeda's franchises elsewhere, like al Shabaab in Somalia? The viability of the threat these groups pose to the U.S. deserves more careful consideration than it has received.

Denial of access by al Shabaab militants, and in some cases by other armed militias, is the single greatest obstacle to the provision of humanitarian assistance in Somalia.

As famine spreads in Somalia, it is more important than ever to ensure that food aid reaches the starving. It's unlikely that the US military, haunted by the memory of Black Hawk Down, will step in. And as long as supply chains are easily looted, hundreds of thousands of Somalis will continue to starve while al Qaeda-linked militants perpetuate conflict and instability in the country.

If it was indeed al Shabaab that trained the Boko Haram militants, then Somalia has become a training center as well as a safe haven for radical Islamist groups. This new role means that al Shabaab is something more than simply an insurgent group; it is also an enabler in al Qaeda’s "far" war against the West and its allies.

The structure and leadership of al Shabaab are of paramount importance to understanding how this radical Islamist group operates in Somalia.

Hizb al Islam may not pose the threat within Somalia and internationally that al Shabaab does, yet it continues to act as a destabilizing force in the country.

In failing to describe the context in which African Union forces operate, a recent Washington Post article misrepresented their brave efforts to respond to attacks by al-Shabab.

A partitioning of southern and central Somalia between al Shabaab and Hizb al Islam has weakened the opposition to al Shabaab and increased the Islamist threat to the western-backed Transitional Federal Government.