Another important incompatibility is based on the separation of powers. A senator who is appointed as a minister ceases to sit in the Senate and is replaced for as long as he is a minister. However, if he resigns as a minister, he may return to the Senate, in accordance with Article 50 of the Belgian Constitution. A senator cannot also be a civil servant or a member of the judiciary at the same time. However, a civil servant who is elected to the Senate is entitled to political leave and doesn't have to resign as a civil servant. It is also not possible to be a member of the Federal Parliament and a Member of the European Parliament at the same time.