In the case of Derrick Kimbrough v. United States in 2007, the U.S. Supreme Court ruled that judges may impose more lenient sentences than federal guidelines suggest for crimes involving crack cocaine. The defendant, a black veteran with no criminal record, was convicted on drug and gun charges and faced a guideline sentence of 19 to 22 years in prison due to the quantity of drugs involved. However, his judge deemed this range excessive given Kimbrough's background and circumstances surrounding his offenses; thus he imposed a lower sentence of 15 years instead. The government appealed this decision arguing it was unreasonable because it deviated from federal guidelines which treated one gram of crack as equivalent to 100 grams of powder cocaine (the so-called "100-to-1 ratio"). This disparity had long been criticized for disproportionately affecting African American defendants like Kimbrough who were more likely to be prosecuted for crack offenses while white defendants were typically charged with powder cocaine offenses carrying lesser penalties. The Supreme Court upheld the lower sentence ruling that sentencing courts could consider policy disagreements with these guidelines including criticisms about their inherent racial disparities when determining appropriate punishments.

In the dissenting opinion for Derrick Kimbrough v. United States, Justice Samuel Alito disagreed with the majority's decision to allow judges more discretion in sentencing individuals convicted of crack cocaine offenses. He argued that this ruling undermines the uniformity and fairness intended by Congress when it established federal sentencing guidelines, which set higher penalties for crimes involving crack cocaine compared to powder cocaine due to its perceived greater societal harm. Alito contended that these disparities were not irrational or arbitrary but based on legitimate considerations such as differences in addictiveness and associated violence between two forms of drugs. He also expressed concern about potential inconsistency and unpredictability in sentences resulting from increased judicial discretion, potentially leading to unjust outcomes where similar offenders receive vastly different punishments depending on individual judge’s views rather than objective standards.