April 21 marks the 50th anniversary of the death of Pedro Albizu Campos. Most Americans likely haven't heard of Albizu Campos or his plan to challenge the United States' control of Puerto Rico. His supporters remember him as an organizer, an intellectual, and a revolutionary. The FBI and the US government labeled him a radical, a terrorist, and a criminal.

Albizu Campos' story and the history of his ill-fated movement are chronicled in War Against All Puerto Ricans: Revolution and Terror in America's Colony, a new book by Nelson A. Denis, a journalist, activist, and former New York state assemblyman. Denis, whose mother is Puerto Rican, says the book would not have been possible without several decades of personal interest and the release of nearly 2 million documents FBI from secret FBI dossiers known as carpetas, gathered over a period of about 50 years. This trove of papers, made public in 2000, reveal a previously untold story about how the US government worked to undermine the growing Puerto Rican independence movement of the 1940s and '50s.

In 1936, Albizu Campos was imprisoned on sedition charges after helping to successfully organize Puerto Rican workers. After more than a decade in prison, he returned to the island and organized an armed revolt in 1950. His plan was never realized, due in large part to FBI infiltration and harassment as well as legal sanctions such as Public Law 53, the "Gag Law," which made it a criminal act to show any outward support for an independent Puerto Rico. The short-lived violent uprising may mark the only time the US military has launched an aerial attack on its own citizens, when National Guard planes strafed the town of Utuado.

I spoke to Denis about Albizu Campos' uprising and why many Americans don't know about the colonial dynamic between Puerto Rico and the United States.

Mother Jones: Why should Americans pay attention to Puerto Rico?

Nelson Denis: Puerto Ricans are Americans. We've been American citizens since 1917. We fought the same battles, made the same sacrifices. We've lost our land in the same way that Native Americans lost their land, and we've been the subject of discrimination and racism in the same way that African Americans have. We've suffered the full spectrum of oppression, and yet we've been off the map 4,000 miles away so we haven't even been able to argue our case. So when people say, "Why should Americans care?" they don't realize that we are 100 percent Americans and we've more than paid the price of admission into this community. ...