I am from Burkina Faso and was a police officer there. I was threatened and attacked by criminals after I arrested a member of their gang. The government would not protect me. Can I get asylum in the United States?
There is no rule stating that a police officer cannot get asylum in the United States. However, if the persecution was a consequence of your job, you will most likely not win asylum.
The first step in an asylum case is to prove that you were seriously harmed. The next step is to prove that the harm occurred on account of your race, religion, nationality, political opinion, or membership in a particular social group. (See "Proving the "Nexus" or Reason for an Asylum Claimant's Persecution.")
Certain professions, such as police officers, military personnel and prison guards, carry an inherent risk of harm. Police officers who are attacked or threatened because of incidents that happen during the course of the job cannot fulfill the “on account of” part of the asylum test.
From your description, it sounds like you were attacked and threatened because you made an arrest while working, not because of your race, religion, nationality, political opinion, or membership in a particular group. Retribution from people who were angry that you made an arrest is a danger you agreed to face when you became a police officer (see Matter of Fuentes, 19 I&M Dec. 658 (B.I.A. 1988)).
This reasoning, however, does not apply to former police officers. If a former police officer was persecuted or fears persecution on account of his or her having been a police officer, it is possible to win asylum. In this case you could prove that the persecution occurred or that you fear persecution on account of a membership in a particular social group, defined as former police officers.