Final answer:
The rise in popularity of supermax prisons in the 1990s was driven by the 'tough on crime' cultural movement, three strikes laws, and the economic interests of the private prison industry. Overcrowding due to the 'war on drugs' and mandatory minimums also contributed to their establishment. As costs and ineffectiveness became clear, the trend started to reverse.
Step-by-step explanation:
The popularity of supermax prisons increased during the 1990s due to a combination of factors. The period was characterized by a law-and-order movement that encouraged a 'get tough on crime' approach, which was popular among policymakers and the voting public. This was a response to a cultural backlash against what was perceived to be a period of excessive leniency. Three strikes laws and mandatory minimum sentencing were implemented, which led to a rapid increase in the prison population.
There was also a considerable influence from the private prison industry, which saw economic benefits in high incarceration rates and therefore had an interest in maintaining and promoting policies that filled prisons. This, coupled with the 'war on drugs' primarily being fought through incarceration rather than prevention or treatment programs, and systemic issues such as racial disparities and sentencing, caused the American prison population to explode from 200,000 inmates in 1970 to 2.2 million by the end of the 20th century.
By the 1990s, the effects of these policies had resulted in overcrowded prisons and state financial burdens, thus supermax prisons appeared as a solution to handle the perceived most dangerous inmates and relieve some of the pressure from standard facilities. However, as the financial and social costs became more apparent, and the effectiveness of mass incarceration as a crime reduction strategy was questioned, the enthusiasm for supermax prisons and the broader 'tough on crime' approach began to wane.