Unión del Pueblo Navarro
The Chartered Community of Navarre (10,391 km²) is a single-province autonomous community. Its name refers to the charters, the "Fueros of Navarre". The Spanish Constitution of 1978 states that Navarre may become a part of the Autonomous Community of the Basque Country if it is so decided by its people and institutions (the "Disposicion transitoria cuarta" or "Fourth Transitory Provision"). To date, there has been no implementation of this law. Despite demands for a referendum by minority leftist forces and Basque nationalists in Navarre, it has been opposed by mainstream Spanish parties and Navarrese People's Union; the ruling party up until 2015. The latter has repeatedly asked for an amendment to the Constitution to remove this clause.