The Supreme Federal Court (STF) is the highest organ of the Brazilian Judiciary, and it is primarily responsible for ensuring compliance with the Constitution, as defined in its article 102. For this reason, the STF is known as the Guardian of the Federal Constitution.
It consists of 11 Justices appointed by the President of the Republic, after approval by the absolute majority voting of the Federal Senate.
One of its main attributions is to judge the direct unconstitutionality act of a federal or state law or normative act. The STF also judges the declaratory action for constitutionality of a federal law or normative act; claims of non-compliance with constitutional precepts and extradition requests by foreign countries.
In the criminal area, the STF judges common criminal offences committed by the President and Vice-President of the Republic, by members of the National Congress, by the Attorney General, by their own members, among others.
The STF also acts as the final Court of decision for ordinary and extraordinary appeals. It judges, as an ordinary appeal, habeas corpus, writ of mandamus, habeas data and writ of injunction decided in a single instance by the superior courts, if the decision is denial, and, as extraordinary appeal, the cases decided in a single or final instance, when the appealed decision contravenes a Constitutional provision.
More information:
http://portal.stf.jus.br