The apex court also made it clear that MPs, MLAs and MLCs would stand disqualified on the date of conviction.
The court said Parliament has exceeded its powers by enacting the provision (Section 8(4) of the Representation of Peoples Act) that gives a convicted lawmaker the power to remain in office on the ground that appeals have been filed and pending.
The court discussed Article 101(3)(a) and 190(3)(a) of the Constitution that deal with the issue of disqualification of MPs of either House of Parliament and MLA and MLCs of the Legislative Assembly or Legislative Council of State respectively.
"We also hold that the provisions of Article 101(3)(a) and 190(3)(a) of the Constitution expressly prohibit Parliament to defer the date from which the disqualification will come into effect in case of a sitting member of Parliament or a State Legislature.
It said as "Parliament had no power to enact sub-section (4) of Section 8 of the Act" and hence, it would not deal with other issues raised in the two PILs filed by a lawyer Lily Thomas and NGO Lok Prahari.
The PILs had sought striking down of this provision on the ground that they violate certain constitutional provisions which, among other things, expressly put a bar on criminals getting registered as voters or becoming MPs or MLAs.