The main purpose of this legislation, known as the "Restoring the Armed Career Criminal Act," is to strengthen the penalties for individuals who are classified as armed career criminals. This is aimed at enhancing public safety by ensuring that those with a history of serious felony convictions face stricter consequences when they commit further offenses involving firearms. Key provisions of this law include significant changes to how sentences are determined for individuals who violate firearm laws after having multiple serious felony convictions.