Why is marbury v. madison an important case? in this case, the justices recognized the authority of congress to regulate the economy of the united states. in this case, the justices nationalized the bill of rights. in this case, the justices authorized the supreme court to exercise judicial review over laws passed by congress. in this case, the justices declared the secession of the confederate states to be in violation of the constitution. in this case, the justices declared that segregation of schools based on race is illegal.