Final answer:
The U.S. Supreme Court's ruling in Brady v. Maryland prevents the suppression of exculpatory evidence.
Step-by-step explanation:
The U.S. Supreme Court's ruling in Brady v. Maryland prevents the suppression of exculpatory evidence. Exculpatory evidence refers to evidence that is favorable to the defendant and can prove their innocence or cast doubt on their guilt. In the case of Brady v. Maryland, the Court ruled that the prosecution is obligated to disclose exculpatory evidence to the defense.