In the context of the current discussion, this older (Jul 05) paper from CEIP is still a good read:

The Key to Arab Reform: Moderate Islamists
...U.S. and European officials understandably worry that Islamists might jettison democratic transition if and when they gain significant power. While understandable, these fears ignore the diversity of the Islamist spectrum. More importantly, policy makers must recognize the more immediate point that democracy cannot come to Arab societies without the participation of movements that command huge popular support. Rather than resisting Islamists, Western governments should develop policies to positively engage the moderates among them...