In recent years, there has been an increase in citizens’ anxiety about violent crimes due to ‘abnormal motives’ resulting in murders and indiscriminate violent crimes. As one of the measures, the government (Ministry of Justice) is seeking to establish a so-called “Life imprisonment without parole”.
 However, there has not been sufficient discussion and social consensus on issues such as whether the system contributes to reducing the rate of violent crime over the introduction of life imprisonment without parole, whether it may violate the Constitution, which values human dignity as the highest value, by fundamentally blocking prisoners’ rehabilitation, improvement, and rehabilitation into society, and whether it increases medical and administrative costs due to overcrowding in prisons and the increase in the number of elderly prisoners.
 In this paper, while keeping in mind the relationship between life imprisonment and the death penalty, we provide an overview of the legislation and application of life imprisonment in the United States, and examine the problems of life imprisonment based on the results of recent important research on life imprisonment. Based on these findings, we examined the legitimacy of the “life sentence without parole” that the Ministry of Justice is currently seeking to introduce.
 Many states in the United States either introduce life imprisonment without parole after abolishing the death penalty, or still retain the death penalty after introducing life imprisonment without parole. Life imprisonment is also applied to non-murder offenses. However, recent legislation and precedent recognize life imprisonment without parole as a cruel punishment with the same characteristics as the death penalty. In other words, life imprisonment without parole places all the blame on criminals, deprives them of hope of rehabilitation and seriously undermines their dignity and humanity as human beings.
 In conclusion, when examining penal reforms, including the abolition of the death penalty, countries with the rule of law should always take humanitarian and human rights considerations as the criteria for the purpose of modern punishment: rehabilitation into society. However, life imprisonment without parole cannot contribute to the realization of the purpose of modern punishment, which is to humanize, rehabilitate, rehabilitate, and resocialize punishment. Therefore, the introduction of life imprisonment without parole as an alternative and sub-sentence to the death penalty should be avoided.