In accordance with the constitutions and legislation of each Member State, or if stipulated in the agreement itself, certain IAs require approval of national parliaments in order to be ratified and enter into force. In most cases, domestic legislation defines the types of IAs requiring parliamentary approval or, in some cases, exceptions for which approval is not necessary. Parliamentary approval normally involves the procedure for the adoption of an act, or in some cases (e.g. UK), parliament need only not object. In the EU, all unicameral parliaments and the lower chambers of bicameral parliaments are always involved. In the 13 Member States with bicameral parliaments, the upper chamber’s role varies. The Belgian and Irish Senates are not involved in ratifications, while the Slovenian National Council has only limited competence in adoption of legislation. In Germany and Austria, the involvement of the upper chamber depends on the treaty type and its relevance for the regions (represented in those chambers). In the remaining Member States (Czech Republic, Spain, France, Italy, the Netherlands, Poland, Romania and the UK) both chambers are involved.