An article in the the Washington Post earlier this week summarizes a secret cable written by the U.S. ambassador to Afghanistan. The cable warned
"that the persistence of enemy havens in
Pakistan was placing the success of the U.S. strategy in Afghanistan in
jeopardy, U.S. officials said. The cable, written by Ryan C. Crocker, amounted to an admission
that years of U.S. efforts to curtail insurgent activity in Pakistan by
the lethal Haqqani network, a key Taliban ally, were failing."
The article does not include specific references to drone strikes from the cable, but notes that drones and other types of force have been aimed athe Haqqani network from some time with little apparent long-term effect.
I'll note that this conclusion is similar to that from a recent paper I co-authored with Megan Smith. We found that drone strikes had little effect on one type of effort produced by terrorist groups--propaganda videos. Al Qaeda's media arm, as-Sahab, has been able to produce a consistent stream of propaganda videos, many of which feature scenes from the regions on the border between Afghanistan and Pakistan, despite drone strikes aiming to disrupt the terrorist groups.