In the United States v. Monsanto case of 1988, the Supreme Court ruled that a defendant's assets could be seized before trial if there was probable cause to believe those assets were obtained through illegal activities and would likely be forfeited upon conviction. The court held that such pretrial asset seizures did not violate the Sixth Amendment right to counsel or Fifth Amendment due process rights. This decision came about when Biagio P. Monsanto, charged with various drug-related offenses, had all his financial resources frozen by federal prosecutors under a provision of the Comprehensive Drug Abuse Prevention and Control Act of 1970 which allowed for forfeiture of any property derived from or used in illegal drug trafficking. As a result, he was unable to hire an attorney for his defense leading him to argue this violated his constitutional rights.

In the dissenting opinion for United States v. Monsanto, Justice Thurgood Marshall argued that allowing the government to seize all assets of a defendant prior to trial, including those necessary to hire legal counsel, violated the Sixth Amendment's guarantee of assistance of counsel. He contended that this ruling would disproportionately affect poor defendants who could not afford an attorney without their seized assets. Furthermore, he criticized the majority's reliance on Caplin & Drysdale v. United States as precedent since it involved forfeiture after conviction rather than before trial and thus did not address whether pretrial asset seizure infringes upon a defendant’s right to retain chosen counsel under adversarial circumstances in criminal proceedings.