Badea has been a member of the Senate of Romania since the 2008 elections. In March 2010, he opened a Parliamentary Bureau in Chişinău.[3] In 2015 he switched from the Democratic Liberal Party to the National Liberal Party.[4]
In the legislature 2008–2012, Badea was a member of the Friendship Parliamentary Groups with Italy, Iraq, Serbia, Albania and Spain. In his parliamentary activity, he was a member of the commission for foreign policy – Deputy Chairperson (until March 2011), Romanians Everywhere Committee - Chairperson and also, at the Committee for privatization and administration of state assets (Mar. - Sep. 2011). He also initiated 41 legislative proposals, out of which 7 laws were promulgated.
In the legislature 2012–2016, Badea was a member of the parliamentary friendship groups with Serbia, Egypt, Norway and Iraq. He was a member of the Committee for foreign policy and the Committee for Romanians everywhere. In the 2016-2020 legislature, he is a member of the parliamentary friendship groups with Lebanon, Oman and the United Arab Emirates.
In addition to his role in parliament, Badean has been serving as a member of the Romanian delegation to the Parliamentary Assembly of the Council of Europe since 2009. In the Assembly, he has been a member of the Committee on Social Affairs, Health and Sustainable Development (since 2021); the Committee on Equality and Non-Discrimination (since 2021); the Committee on the Honouring of Obligations and Commitments by Member States of the Council of Europe (since 2020); the Sub-Committee on the European Social Charter (since 2018); the Sub-Committee on Children (since 2017); the Sub-Committee on the Rights of Minorities (since 2017); the Committee on Political Affairs and Democracy (2012–2013); and the Committee on Culture, Science, Education and Media (2012–2013).[5] For the 2018 Azerbaijani presidential election, he led the Assembly's monitoring mission.[6] In 2021, he served as the Assembly's rapporteur on the impact of labour migration on left-behind children.[7]