The Trump Administration's most recent proposal to prevent terrorists from entering the country is to undertake "extreme vetting" in the form of disclosing contacts on their mobile phones, social-media passwords and financial records, and answering probing questions about their ideology.

This brings to mind the nature of the more general Terrorist Screening Game, in which The Government establishes rules and procedures for Screeners to follow in an attempt to weed out Terrorists from Non-Terrorist Visitors and Immigrants into the country.

This analyzes examines the objectives of players in the Terrorist Screening Game and considers relevant questions and issues.

Players

A. The People or Potential Victims of Terrorists Attacks

Two potential objectives of The People are

• To feel safe from terrorist activity

• To have a low probability of being the victim of a terrorist attack

B. The Government

The Government establishes rules and procedures to be used by screeners (both physical and informational) of visitors and immigrants into the country. The Government may have any of several objectives:

• To make The People feel safe from terrorist activity

• To decrease the probability of terrorist attacks

• To increase the size and power of The Government

The Government must be able to come up with rules and procedures that

• Can scale

• Can be implemented by the average Joe (i.e., not require particular expertise)

For The Government to be able to establish rules and procedures to be used by screeners, it must be able to distinguish Terrorist from Non-Terrorist Visitors and Immigrants.

C. Physical (TSA) and informational (Customs) Screeners

Screeners apply the rules and procedures established by the Government to screen all (Terrorist and Non-Terrorist) Visitors and Immigrants to the country.

D. Terrorists

Terrorists have two main objectives:

• To evade detection as Terrorists and enter the country

• To terrorize The People

E. Non-Terrorist Visitors and Immigrants to the Country

Points to Ponder

• What physical or informational characteristics distinguish Terrorists from Non-Terrorist Visitors and Immigrants?

          Since Terrorists want to evade detection, they will try to hide characteristics that distinguish them from Non-Terrorist Visitors and Immigrants.

          Some distinguishing characteristics of Terrorists include:

Who they associate with (other terrorists)

Who they communicate with (send and receive info)

Places they visit (real and virtual)

Possessions (e.g., weapons or bomb-making materials)

Actions they take

Known names/aliases

• Given the distinguishing characteristics, what rules and procedures can the Government use for screening that will satisfy the objectives of The People?

Make them feel safe

Minimize probability of terrorist attacks

Make people feel safe but not actually increase their safety

• What rules and procedures can the Government use for screening that will satisfy the objectives of The People and at the same time minimize the inconvenience to Non-Terrorist Visitors and Immigrants?

• Clearly, there is a tension between thoroughness and/or effectiveness and inconvenience to Non-Terrorist Visitors and Immigrants.

This becomes more difficult to achieve over time as Terrorists learn to better mimic Non-Terrorist Visitors and Immigrants

• What rules and procedures can the Government use for screening that will satisfy the objectives of The Government?

To increase the size and power of The Government

And make The People feel safe

And minimize the probability of terrorist attacks

• What factors limit Government’s ability to act?

Non-discrimination/profiling

Limited resources

Bureaucracy

Potential to act covertly limited

Actions must be scalable

Actions must be able to be implemented by average people

• If there were no limitations on government, how could it minimize probability of terrorism?