In the 1980s and 1990s, Biden supported many "tough on crime" laws.
Some aspects of these laws were controversial. For example, the Anti-Drug Abuse Act of 1986 made a distinction between crack cocaine and powder cocaine, even though these two drugs are pharmacologically very similar. The distinction meant that those caught with crack cocaine received much harsher sentences than those caught with powder cocaine, and these measures disproportionately affected black people. Biden has called parts of the 1986 Act "a profound mistake".
The 1994 Crime Bill set much harsher sentences for those using drugs. Biden authored this Bill, which again disproportionately affected black people an introduced a "three strikes" policy.
Under these laws, many were incarcerated for nonviolent drug crimes. Some were even sentenced to life.