Why was the ruling in furman v Georgia struck down?

The ruling in Furman v. Georgia (1972) was struck down because the Supreme Court found that the death penalty was applied in an arbitrary and capricious manner, violating the Eighth Amendment's prohibition against cruel and unusual punishment. The Court highlighted the lack of consistent guidelines for imposing the death penalty, leading to discriminatory enforcement, particularly against marginalized groups. This decision effectively halted capital punishment across the United States until states could revise their laws to address these constitutional concerns.