Terrorists kill to spread terror, hence the name. A terrorist attack is, by definition, an attack against random civilians for the pure purpose of intimidating a population. Basically, everybody in the terrorist targeted population is a target.
This is a real problem from the security perspective. Even a small country or ethnic group has millions of members. If a terrorist just needs to kill a handful of them out of millions to have a successful attack, he can attack anywhere and at anytime. This makes terrorists nearly impossible to stop if they have the least foothold within a society. They get to pick the time and place of the attack.
It is easy to be a big shot terrorist who can pick from thousands of miles of street, tens of thousands of buildings and any time over a period of months. You can strike without warning and easily escape before any authority can catch you. However, what happens to if you are forced to attack a few heavily guarded sites on a particular day?
I think the elections today in Iraq will serve as a lethal honey-pot for the terrorists. All the polling sites will be heavily guarded. They will have to fight prepared forces in order to strike them. No more skulking about, choosing the time and place to strike. They will have the time and place imposed on them. If they don’t fight, they will be further exposed as paper tigers.
I predict that (1) election violence will be far less severe than most fear, because the terrorists will not like the odds, and that (2) attacks which do take place will largely fail with heavy casualties.
(Update: Well the polls have closed, violence was low. The terrorists barely made an appearance. They suffered a huge defeat here. Perhaps we need to come up with a strategy wherein we create situations that require the terrorists to strike at specific times and places or risk losing face.)