on findingsStudent entries

The impact of 9/11 on terrorism prosecutions


This continues our series of student reflections and analysis authored by our research team.


In my last blog post, I discussed how cases are deemed fit for inclusion in the tPP database. That post ended with a question about when and why crimes without a clear political motive are labeled as terrorism by the government. As the tPP team segued into its analysis phase, this question guided my research.

My suspicion was that the occurrence of 9/11 had a significant impact on the types of cases being prosecuted as terrorism. In my experience coding cases, I spend a lot of time looking at the post-9/11 sweep cases. These usually involve immigration violations by Arabs and are labeled as terroristic by the government. To investigate this further, I divided the data by time periods to look for differences in the data before and after 9/11. I also specifically looked at the year immediately following 9/11.

I focused my analysis on seven variables that could show which crimes are non-violent and non-political. Some markers of these cases are that they are ideologically unaffiliated, the tactic is a non-political criminal violation (such as an immigration violation), and the defendant is “othered.” I used descriptive statistics to look at the frequencies of these traits in cases before and after 9/11, and I used a chi-square analysis to test for significance.

The most noteworthy findings from my analysis are as follows.

  • The frequencies of values for all seven variables I tested were significantly different in the year after 9/11 compared to the whole dataset. This indicates that that year is not representative of all terrorism prosecutions since 1990. The cases in that year are significantly different from the dataset as a whole.
  • Of the seven variables, five of them were also significantly different between the year after 9/11 and the year leading up to it. This accounts for the varying political climates that may affect the larger dataset. This two-year span was subject to the same political and social climate, with the exception of 9/11.
  • There were zero instances of cases with a tactic of a criminal violation not motivated politically prior to 9/11. When there was no political motivation for a crime before 9/11, the government never called it terrorism. In the year following 9/11, 52.4% of cases fell into this tactic category.
  • There were zero instances of deportation in the dataset prior to 9/11. In the year after 9/11, 16.9% of cases ended in deportation.
  • Of all the cases in the dataset ending in deportation, over 60% of them occurred within one year after 9/11. 85.7% of them were defendants who were ideologically unaffiliated. 63.6% of them had a non-political criminal violation tactic.

While my analysis of these cases will continue as the dataset expands, my initial findings seem to confirm my expectations. 9/11 had a significant impact on the government’s prosecution and labeling of terrorism, especially in the immediate aftermath. As I continue to interpret these cases, I plan to look deeper into the long-term implications of 9/11 for non-political crimes.

Lauren Donahoe is a senior biology major and a senior team member of the Prosecution Project. She has been with the project since Fall 2017.

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