My reasoning is as follows: the world is an increasingly dangerous and chaotic place. The United States will face continuing demands to act as its "policeman," demands that over time cannot be resisted or ignored.
Acting as disturbance-handlers isn't the role our regular Army and Marines are designed or trained for. A model of what is needed already exists - the French Foreign Legion. It has been the de facto policeman of French Equatorial Africa since the 1830s.
La Legion Etrangere c'est le gendarme de l'Afrique.An unintended but very real side benefit: the quasi-colonial aspects of a foreign legion. American officers leading third-world troops will infuriate the anti-colonialists among us, most notably our incumbent President. Irritating Obama will be absolute karma after all the times he's irritated us.