When missionaries arrived in Hawaii in the 1830s, they brought with them a new set of moral and legal codes. As a result, the death penalty was abolished and replaced with a sentence of exile. The island was chosen as an obvious place for this new form of punishment, but this only lasted until 1853. In 1857 only about 50 people lived on the island and the government opened it up for ranching. Though at time successful, the unreliability of rainfall and lack of fresh water sources made ranching very difficult. One of these ranchers, Angus MacPhee, leased a portion of his land to the U.S. Army in early 1941. After the attack on Pearl Harbor, the U.S. government instituted martial law and took over control of the island and began its the decades-long use of it as a training/bomging ground. Hawaiian efforts to stop this use began in the 1970s. It wasn't until 1990 that this officially ceased. Efforts to clean up the island of unexploded ordinance and restore its natural state continue today.