Some people are legally prohibited from becoming refugees or asylees in the United States. In other words, despite the fact that they may have been persecuted in their home country, and fear for their safety if they return there, they are categorically ineligible for asylum or refugee status. (This comes from the Immigration and Nationality Act at I.N.A. § 101(a)(42), 8 U.S.C. § 1101(a)(42); I.N.A. § 241(b)(3), 8 U.S.C. § 1231(b)(3); and from certain of the grounds of inadmissibility at I.N.A. § 212.)
These laws bar anyone who has been:
There is no list of particularly serious crimes—the decision is made case-by-case. However, all "aggravated felonies" are considered particularly serious crimes. Because of the immigration laws’ strict definitions of aggravated felonies, some crimes that may have been called misdemeanors when committed will be looked upon as aggravated felonies. For more information, see What's an "Aggravated Felony" Under U.S. Immigration Law?.
Applicants whose crimes were non-serious or political in nature may still qualify for refugee or asylee status.
The definition of a terrorist includes having been involved in such illegal activities as assassination; violent attacks upon an internationally protected person; hijacking or sabotaging a means of transport; using explosives, firearms, or other devices to endanger others or cause substantial damage to property; seizing, detaining, and threatening to kill, injure, or continue to detain people in order to compel a governmental organization or someone else to act; and more. It also includes giving food, money, or other material support to organizations that the U.S. government believes to be terrorist in nature (with possible exceptions if a person did so under duress, for example at gunpoint).
This can include ordering, inciting, assisting, or otherwise participating in genocide, torture, extrajudicial killings, or other abuses based on the victims’ race, religion, nationality, membership in a particular social group, or political opinion. For example, this rule is often used to deny refugee status to military or police officials who assisted in persecuting minority or guerrilla groups (even though they may, indeed, fear for their life because members of those groups are seeking revenge against them).
This includes arbitrary prohibitions or punishment for freely worshiping, preaching, praying, changing religions, and more.
If you fear returning to your home country, but believe you may be affected by one of the bars described above, by all means consult with an experienced U.S. immigration attorney before you submit an application. The attorney can help you evaluate whether applying for asylee or refugee status is likely to help your situation, and if it is, how to present a compelling application.