Domestic terrorism is generally underestimated, especially within the United States: when a terrorist attack occurs the first reaction is to presume that it was committed by foreigners. That presumption was made for example in the case of the Oklahoma City bombing. The revelation that the attack was actually committed by Americans as opposed to foreigners was a shock to the people of the United States and served as an embarrassment to the United States media.
It is of notable interest to consider the political expediency of declaring violent actions to be terrorism. Throughout history many actions against the existing establishment have been, in their day, considered terrorism. History has in some cases judged them differently. While the vast majority of acts of violence are unjustified, human history has shown that violence is sometimes the last/only means to effect change.