What did the case of marbury v. madison establish for the courts, and what does that mean? equal power for the legislative and executive branches of government was established which means both had to follow the laws outlined in the constitution. "due process" was established which means the government must respect all of the legal rights owed to a person under the constitution, even if that person is accused of a crime. "freedom of expression" was established, which means citizens can seek, receive, and impart information orally, or in writing, without censorship. the court's power of judicial review was established which means the court has the power to review and determine if laws or acts of government are unconstitutional.