What is anti-defection law?

The anti-defection law was enacted to ensure that a party member does not violate the mandate of the party and in case he does so, he will lose his membership of the House. The law applies to both Parliament and state assemblies.

The Tenth Schedule was inserted in the Constitution in 1985. It lays down the process by which legislators may be disqualified on grounds of defection by the Presiding Officer of a legislature based on a petition by any other member of the House. 

A legislator is deemed to have defected if he either voluntarily gives up the membership of his party or disobeys the directives of the party leadership on a vote. This implies that a legislator defying (abstaining or voting against) the party whip on any issue can lose his membership of the House.

Further Reading:

• Anti-Defection & Role Of Speaker
• Indian Polity Notes For UPSC