Security assistance depends on supporting both the militaries and the governments in weak states. Critics argue that security assistance undermines local government institutions and enables undisciplined host-nations to abuse human rights. Why should the U.S. struggle to build strong armies in weak states? Engaging weak states is in our interest, say the authors, because weak states often have governments that lack legitimacy and national identity, and thus provide environments conducive to insurgency and terrorism. Nonetheless, if we offer the right combination of carrots-and-sticks, we can encourage host-nations to reform their armed forces without undermining domestic political stability.