The top court also opined that Parliament should reconsider "strengthening certain aspects of the Tenth Schedule, so that such undemocratic practices (of defections) are discouraged."
A bench, headed by Justice N.V. Ramana, upheld the decision of the then Karnataka Assembly Speaker to disqualify the 17 rebel MLAs of Congress and JD(S) in July but struck down the order of their disqualification till the end of the Assembly's term, saying the Speaker has no powers to direct that.
The resignation by these legislators of the then ruling coalition of JD(S) and Congress had led to the fall of the H.D. Kumaraswamy government.
There is a growing trend of Speakers acting against the Constitutional duty of being neutral, the court said.
"The Speaker has no power under the Constitution to disqualify the members till the end of the term," it said.
The court, however, refrained from commenting on the validity of the resignations.
It emphasised on the Constitutional morality, saying the Speaker can only examine whether the resignation is voluntary or otherwise.
It said there is no doubt that disqualification takes place when there is defection.
The defection had happened before the resignation and therefore, the tenet of disqualification does not vanish, the court said.
At the same time, the apex court emphasised the Speaker should disassociate from his political party and should not behave contrary to the spirit of the neutrality and independence, "such person does not deserve to be reposed with public trust and confidence".
The Supreme Court observed that the object and purpose of the Tenth Schedule is to curb the evil of political defection, motivated by the lure of office or rather similar considerations which endanger the foundation of our democracy.
"The case mostly turns on the fact that there is ample evidence to portray that the defection of these petitioners had occurred even before they resigned," observed the court.
( With inputs from IANS )