It will lead to the "preference" of the executive government playing a role in the selection process.
"First, the proposed change appears to be unconstitutional as it is violative of Article 320. The selection for 'appointment' to the service, now done solely by the UPSC, will be affected by the foundation course marks given by the executive government," Chidambaram wrote in a blog post.
"I doubt if the proposed change can be implemented without amending Article 320," he said.
The Congress leader said the move will "greatly" affect the anonymity and objectivity of the selection process.
"Preference of the executive government and subjectivity will play a role in the allotment of service and cadre. Neither factor is desirable. There is a clear and present danger," he said.
The remarks came a day after Congress President Rahul Gandhi criticised the government's proposal saying it wanted to appoint officers of "RSS's choice".
The Department of Personnel and Training has written letters to all cadre-controlling ministries seeking their comments on the Prime Minister's Office proposal asking if probationers should be allocated the services and cadre after reviewing their performance in the three-month foundation course besides the score obtained in the Civil Services Examination.
Chidambaram said that despite their strengths and weaknesses, the All India Services have by and large served the country well since the selection of cadre is done by, or on the recommendation of, the Union Public Service Commission (UPSC) and is believed to be totally objective.
"There is anonymity in the written examination and there is objectivity because the examination and the interview are conducted by the UPSC. The Executive has absolutely no role to play. This is consistent with Article 320 of the Constitution," he said.
Article 20 mandates that "it shall be the duty of the union and state public service commissions to conduct examinations for appointments to the services of the union and the services of the state respectively".
The Congress leader said if the foundation course marks are taken into account for allocation of service and cadre, it will compromise the transparency and objectivity of the process since the course is conducted by officers appointed by and answerable to the executive government.
"Is the central government planning another disruption? And if yes, why?" he asked.
(This story has not been edited by Social News XYZ staff and is auto-generated from a syndicated feed.)
