The court system is able to perform judicial review of laws, i.e. check if they are constitutional. This right is not included in the constitution, but was established by the Supreme Court in the beginning of the 20th century, when it decided to hear cases about the constitutionality of land laws. While this right was contested in the beginning, the political system eventually accepted it. The Supreme Court have been reluctant to rule laws unconstitutional; the only time it have done so was in 1999, when it found that the Tvind law breached the principle of separations of power. Cases about the constitutionality of laws can only be initiated by people directly affected by the laws. All can do this with respect to the Danish relation to EU, because of its wide effects on society.