Advocacy campaign Unlock the Box launched an 18-day campaign to tell President Joe Biden to end solitary confinement in federal jails and prisons on Nelson Mandela International Day (July 18). Mandela was incarcerated in apartheid South Africa for 27 years; of those he spent 18 years in solitary confinement.

Unlock the Box says that during the presidential campaign, Biden promised to end solitary confinement “with very limited exceptions such as protecting the life of an imprisoned person,” according to his campaign website. More than six months into his presidency, Biden has not acted on ending solitary confinement.

In June, more than 150 groups, including Unlock the Box, sent an open letter to the Biden administration urging him to “end the pain, torture, and trauma of tens of thousands of people languishing in harsh and harmful conditions.” Also last month, the Federal Anti-Solitary Taskforce, of which Unlock the Box is a member, released a blueprint on how the Biden administration can end solitary confinement.

There are approximately between 60,000 and 100,000 people in solitary confinement. Of those, more than 10,000 are held in federal prisons and jails. As many as half of people in solitary confinement suffer from mental illness, which is often exacerbated by isolation.