The Constitution (Fifty-second Amendment) Act, 1985, is a constitutional amendment that introduced the Anti-Defection Law in India. It was enacted to address the problem of frequent political defections by elected representatives, which had caused significant political instability, famously dubbed "Aaya Ram, Gaya Ram" politics, with nearly 50% of legislators defecting between the 1967 and 1971 general elections. The Act was assented to on February 15, 1985, and was introduced by Rajiv Gandhi.
The Amendment works by inserting the Tenth Schedule into the Constitution, which lays down the provisions for the disqualification of Members of Parliament (MPs) and Members of State Legislatures (MLAs) on the ground of defection. A legislator can be disqualified if they voluntarily give up the membership of their political party, or if they vote or abstain from voting in the House contrary to any direction (whip) issued by their party, unless the party condones the action within 15 days. The question of disqualification is decided by the Chairman or the Speaker of the respective House.
The Amendment also made consequential changes to Articles 101, 102, 190, and 191 of the Constitution. The law was subsequently amended by the Constitution (Ninety-First Amendment) Act, 2003, which removed the provision that allowed defection without disqualification in the case of a 'split' in a political party. The 91st Amendment also added a provision that a member disqualified on the grounds of defection cannot hold any ministerial or other remunerative political post until their term expires.