Well, if you view insurgency as a means to political end, then if you can knock other players out of the fight you get closer to your desired strategic endstate. so if you can't beat somebody by force of arms, you attack them where their achilles' heel is. In our case it is the political willpower in the United States. Regretably, the political parties have made national security a political issue when we are ina a war. Personally, I think this is a catastrophic mistake. The Democrats should have conceded this issue to the GOP, and focused on other issues that they can get traction on. So the insurgents are playing on our election cycle, not suprised.