From the Oklahoma City bombing, until 9/11/01, the worst act of terror on U.S. soil, to the Atlanta Olympic bombing of 1996, to numerous abortion clinic bombings, most acts of domestic terrorism have been carried out by Christian fundamentalist groups/individuals.
Timothy McVeigh was known to be associated with the Christian fundamentalist/white supremacist group Christian Identity. A group called the Army of God lead by (according to FBI files) Eric Robert Rudolph(like Osama bin Ladin, apparently still at large) claimed responsibility for the Atlanta Olympic bombing as well as a number of abortion clinic bombings. There are a number of "Christian Patriot" groups that have been involved in bombings and other terrorist attacks/threats, mostly against abortion clinics/doctors.
From the Federal Courts to anyone associated with abortion clinics and family planning centers and any other likely targets of Christian fundamentalist domestic terror, we need to increase security measures and vigilence as much if not more so, as we have against international terror(bin Laden, etc.).
Any self-proclaimed Christian individual/group with a fundamentalist "it's our way or no way" attitude should come under much greater scrutiny, as they are just as capable of terrorism, as we have seen with McVeigh and the "Army of God", as bin Laden and Al Quada, especially since most are right here under our noses.