With the exception of ethnic minority parties, only candidates of political parties receiving at least 5% of the total national vote can enter the Sejm. When sitting in a joint session, members of the Sejm and Senat form the National Assembly (the ''Zgromadzenie Narodowe''). The National Assembly is formed on three occasions: when a new president takes the oath of office; when an indictment against the President of the Republic is brought to the State Tribunal (''Trybunał Stanu''); and when a president's permanent incapacity to exercise his duties due to the state of his health is declared. To date, only the first instance has occurred.