The Prime Minister should be from Lok Sabha
On 30 May 2013, Prime Minister Manmohan Singh was elected to Rajya Sabha for the fifth consecutive term as Congress won both the seats to the Upper House from Assam. The Indian Constitution does not lay down that the Prime Minister necessarily be a member of the Lok Sabha. Nor do the conventions established in India; require that the P.M. be a Lok Sabha member.
However, it has been argued by some in view of the spirit of the Constitution the P.M. should be a member of the directly elected house. It is stressed that in almost every functioning parliamentary democracy the accepted practice is that the head of the government is a member of the directly elected house.
But such argument surely glosses over some facts. It is U.K. which is most often cited as an example of Parliamentary democracy wherein the P.M. should necessarily be a member of the House of Commons. However, the fact that ministers of one house cannot take part in proceedings of the other house in U.K. is often overlooked. Moreover, it needs to be laid out that the House of Lords is a completely non-representative body, unlike the Rajya Sabha, whose members are mostly elected from the states, though indirectly.
However, keeping in mind the spirit of the Constitution, it is desirable that the P.M. be a member of the popular house. However, it should not be a rigid condition, as at times the best suitable person may be a Rajya Sabha member. It would not serve the interest of anyone to deny the post of P.M. to a suitable person, on the ground that he belongs to one house, not the other. Thus though it is desirable, yet it should not be made a qualifying condition.