The fallacy of guilt by association occurs when an arguer transfers a negative attribute onto a target (such as a belief, person or group) from a source that somehow has a connection to, or a characteristic in common with, that target.

Here is an example:

1. All three of Albert's college roommates were punished for "disturbing the peace" after they thought it would be funny to blast loud rock music in the library during finals week.

2. So, Albert is surely guilty of mischief on campus as well.

This overlooks the real possibility that Albert may not share this type of guilt with his roommates despite living under the same roof with them.

A general template of this fallacy is:

1. A is somehow associated with B.

2. B is bad or wrong (often left unstated).

3. Therefore, A is bad or wrong (often in the same way that B is bad or wrong).

The target of this fallacy does not have to be a person; it can be an opinion, belief, ideology, etc., as in the following example:

1. The most ruthless Mafia leaders -- people with criminal minds -- were members of the Catholic Church.

2. Therefore, Catholicism is for criminal minds.