In the late 1960s and 70s, defections (elected legislators changing parties after the election) in Parliament and State Legislatures became very frequent, so frequent in fact, that the epithet "Aaya Ram Gaya Ram" was coined to describe the same.  To curb this problem which created instability in our legislatures, Parliament amended the Constitution.  They inserted the Tenth Schedule to the Constitution "to curb the evil of political defections".  As a result, we currently have an anti-defection law with the following features: 1.  If an MP/MLA who belongs to a political party voluntarily resigns from his party or, disobeys the party "whip" (a direction given by the party to all MPs/ MLAs to vote in a certain manner), he is disqualified.   The party may however condone the MP/ MLA within 15 days. 2.  An independent MP/ MLA cannot join a political party after the election. 3.  An MP/ MLA who is nominated (to the Rajya Sabha or upper houses in state legislatures) can only join a party within 6 months of his election. 4.  Mergers of well-defined groups of individuals or political parties are exempted from disqualification if certain conditions are met. 5.  The decision to disqualify is taken by the Speaker/ Chairman of the House. The table below summarizes provisions of anti-defection law in some other countries.  (For more, click here).  As one may note, a number of developed countries do not have any law to regulate defection.