[Author's Note: I had a longer post on this, but Weebly decided to delete all but the first sentence when I tried to post it. So it's mostly links. Thanks, Weebly.]
Daniel Byman and Will McCants have an interesting piece in The Washington Quarterly on how to avoid 'forever wars.' They offer some red lines on when to intervene against terrorist groups to add some order to how we engage them. It's good advice even if implementation might get a bit sticky.
Any time I read about safe havens I return to an article by Elizabeth Arsenault and Tricia Bacon that is truly excellent. They provide a typology of safe havens and policy advice for each quadrant of the typology (huzzah for two-by-twos!). It's my favorite piece on the topic and as it focuses on how to work with host governments. You should read it.