I compiled a pair of graphs to illustrate incidents of terrorism during each of the last three presidents, including President Obama, as a means of locking down what happened and when.
In terms of methodology, I covered the following types of terrorist attacks against American personnel, civilians and interests:
1) Domestic (Abortion-related attacks, Oklahoma City, Unabomber, Anthrax)
2) Domestic Islamic (9/11, WTC 1993, Beltway Snipers, Chapel Hill)
3) Overseas Islamic (Iraq, Afghanistan, USS Cole, Embassy Bombings)
4) Known Failed Attempts (Shoe Bomber, Underpants Bomber)
5) Overseas Attacks Against U.S. Allies (London, Madrid).
These categories should cover the basic forms of terrorist attacks against Americans whether abroad or on our soil.
UPDATE: I created a third graph as a variation of the attacks graph. I eliminated Obama, as he's only been president for 11 months. I also dropped the domestic abortion attacks and the failed attacks. Additionally, I eliminated any attacks that took place in Iraq and Afghanistan. The resulting graph, reflecting only domestic and Islamic terrorism, is still pretty damning of the Bush record. I also added a Domestic Islamic attack in the Bush column -- the Chapel Hill SUV attack.
Regarding Iraq and Afghanistan, I recommend taking a look at this link. The number of overseas attacks against U.S. targets outside of Afghanistan and Iraq during the Bush presidency are considerable. 11 attacks according to this source, all involving U.S. personnel.
UPDATE 2: Made some small numerical corrections to the attacks graphs.
UPDATE 3: Added the Holocaust Museum shootings to the Obama column.
(A more thorough listing of sources after the jump...)
The number of terrorist attacks are as close to comprehensive as possible. I culled the lists of attacks and total fatalities from the following sources:1) Chronology of Major Terrorist Attacks Against U.S. Targets2) Terrorist Attacks (within the United States or against Americans abroad)3) Notable attacks associated with domestic terrorism4) The Unabomber5) Abortion Violence in the United States6) Beltway Sniper Attacks (which were prosecuted under terrorism laws)7) Ft. Hood Shooting (I've classified this as a domestic Islamic terrorist attack as a concession to righties.)8) The LAX Shooting9) Madrid Train Bombings10) London Bombings11) Anthrax Attacks12) Richard Reid (Shoe Bomber)13) Umar Farouk Abdulmutallab (Underpants Bomber)--I tried to be as fair as possible. I have included the Beltway Snipers, for example, as a terrorist attack because they were prosecuted under terrorism statutes. In exchange, I have made a concession to classify the Ft. Hood shootings as an act of terrorism rather than as a multiple homicide.--Also, I don't claim 100 percent accuracy on the totals, but they're as close as possible based upon the above sources. I would estimate a margin of error around +/-3 attacks, and +/-100 fatalities.--You will also see that the fatalities under Bush were considerable. That number includes the 2,992 fatalities on 9/11, along with the 10 Beltway Sniper fatalities and the 2 LAX shooting fatalities. All three attacks were carried out by Islamic radicals.--The Clinton domestic number is pretty large due to the number of abortion-related attacks by right-wing extremists. There were, based on my sources, 13 abortion-related attacks with 12 fatalities.--Due to the limitations of the graph here are the Obama attacks: Two attacks in Iraq with a total of 9 fatalities, Ft. Hood with 13 fatalities, Abortion shooting of Dr. Tiller, the CIA bombing in Afghanistan with 7 fatalities, and the failed Underpants Bomber.--Also, I'm open for questions in the comments and I reserve the right to make edits to the numbers. In other words, consider this quasi-open source.--Here's the specific attacks and fatalities from the revised graph contained in the UPDATE above.
(Not including abortion clinic attacks)
1) World Trade Center 1993 (Domestic Islamic) - 6 fatalities
2) Oklahoma City (Domestic) - 168 fatalities
3) Riyadh, Saudi Arabia (Overseas Islamic) - 5 fatalities
4) Khobar Towers (Overseas Islamic) - 19 fatalities
5) U.S. Embassy Bombings (Overseas Islamic) - 224 fatalities
6) USS Cole (Overseas Islamic) - 17 fatalities
7) Unabomber (Domestic) - 3 fatalities
8) Atlanta Olympics (Domestic) - 2 fatalities
(Not including Iraq and Aghanistan attacks, and abortion attacks)
1) September 11 (Domestic Islamic) - 2,992 fatalities
2) Karachi (Overseas Islamic) - 12 fatalities
3) Riyadh (Overseas Islamic) - 34 fatalities
4) Riyadh #2 (Overseas Islamic) - 22 fatalities
5) Riyadh #3 (Overseas Islamic) - 4 fatalities
6) Jeddah (Overseas Islamic) - 4 fatalities
7) Amman (Overseas Islamic) - 57 fatalities
8) Damascus (Overseas Islamic) - No fatalities
9) Athens (Overseas Islamic) - No fatalities
10) Algeria (Overseas Islamic) - 60 fatalities
11) LAX Shooting (Domestic Islamic) - 2 fatalities
12) Beltway Snipers (Domestic Islamic) - 10 fatalities
13) Anthrax (Domestic?) - 5 fatalities
14) Madrid (Overseas Islamic Allies) - 191 fatalities
15) London (Overseas Islamic Allies) - 56 fatalities
16) Chapel Hill SUV attack (Domestic Islamic) - No fatalities
17) Yemen (Overseas Islamic) - 16 fatalities
18) Mumbai, India (Overseas Islamic) - 190 fatalities