Bill Roggio talks about the cross-border attacks in Pakistan's northwestern province of Waziristan carried out over the last several weeks by American forces.
The problem is that al Qaeda is using training facilities and safe houses in western Pakistan to train and prepare for further attacks on American soil which leaves us with two options. We can do nothing and hope that the Pakistanis will, counter to all experience, purge the Taliban and al Qaeda from these territories themselves, or we can try to disrupt their planning and training by attacking these facilities ourselves and killing the terrorists. This last carries with it substantial costs since it threatens to undermine the Pakistani government and thus our relationship with it. Unfortunately the risks associated with doing nothing are even greater.
Roggio's analysis is a good read.
RLC