A political prisoner is someone who is imprisoned specifically for their political beliefs.
The practice of imprisoning a person merely for their political views is highly controversial. Most nations aspiring to democracy have constitutional safeguards protecting citizens from becoming political prisoners. In the United States, protections like the First Amendment prevent the government from taking many political prisoners.
Political prisoner is a term typically used by those opposing a regime’s imprisonment of an individual or individuals through accusing the regime of trying to silence dissent. Throughout history, many famous activists have been held as political prisoners, including Martin Luther King Jr., Nelson Mandela and Mohandas Gandhi.
Many times, governments object to accusations that they’ve imprisoned someone as a political prisoner, and point to acts of civil disobedience and other crimes as the primary purpose for imprisoning an individual.