According to the Constitution of Estonia (Estonian: Põhiseadus) the supreme power of the state is vested in the people. The people exercise their supreme power of the state on the elections of the Riigikogu through citizens who have the right to vote. The supreme judicial power is vested in the Supreme Court or Riigikohus, with nineteen justices. The Chief Justice is appointed by the parliament for nine years on nomination by the president. The official Head of State is the President of Estonia, who gives assent to the laws passed by Riigikogu, also having the right of sending them back and proposing new laws.
What document declares supreme power for the people?
the Constitution of Estonia