"The moment he resigns from the Union Cabinet, he ceases to be the Leader of the Lok Sabha and hence, cannot be said to be holding the office of profit," senior advocate Harish Salve told a five-judge Constitution bench headed by Chief Justice Altamas Kabir.
Salve, appearing for Mukherjee, said either the Prime Minister is the Leader of the Lower House or he can nominate a minister in his place.
Mukherjee ceased to hold the office of Leader of the House as a result of his relinquishing the post from the Cabinet and hence, the allegation that Lok Sabha website showed Mukherjee as the leader even after filing of his nomination for the Presidential poll was of no consequence, Salve said, adding that the plea deserves to be dismissed.
Initiating arguments before the bench, also comprising justices P Sathasivam, SS Nijjar, J Chelameswar and Ranjan Gogoi, senior advocate Ram Jethmalani, counsel for Sangma, objected to the mode of Mukherjee's resignation from the post of Leader of Lok Sabha.
"The letter (for resigning from post of Leader of Lok Sabha) is not addressed to any Constitutional authority but was addressed to the Party President. The Speaker of the House, under various rules, has to deal with this issue. Mode of relinquishing the office is much more complex and requires a role of the Speaker," he said.
In his petition, Sangma had said the veteran Congress leader was not eligible for the post as he was holding offices of profit on Jun 28, the day he filed his nomination for the President's election.
Jethmalani alleged that Mukherjee remained an MP till the time he assumed the office of President as "the official website of Lok Sabha, updated from time to time, showed him as the Leader of the House till Jul 30."
"You should have pre-requisites of becoming an MP but you should not be an MP at the time of being elected as the President," he said.
Jethmalani also raised doubts over authenticity of Mukherjee's resignation from the post of Chairperson of the Indian Statistical Institute (ISI), saying "all this raises a serious question of facts and law".
He cited provisions of the Civil Procedure Code to drive home the point that a "tentative" response to the allegations should not have been filed.
The veteran lawyer said that no issue can be decided on the basis of an affidavit (of Mukherjee) and "the final hearing has to be on the basis of documents, witnesses, their examination-in-chief and cross examinations."
Later, during the day, Salve rebutted the contentions saying that while dealing with the election of the "highest office of the land", the CPC will have a "very limited" role and the rules framed by the Supreme Court will deal with it."
"If the Supreme Court has framed rules then the CPC is on a different footing ... The CPC is out and it will not apply on the petitions filed regarding the elections of President and the Vice President," he said.
Dealing with the issue of the post of ISI's Chairperson and subsequent resignation, Salve said it was an "honorary" post with no salary, perks and perquisites.
"Where is the profit? Please see the Act/Rules/Bye laws of ISI ... no salary, no perks and it is the matter of law," he said.
On the issue of Leader of Lok Sabha, Salve said, "on Jun 25, the Congress Working Committee held a farewell (for Mukherjee). It is absurd that he held the office of profit till Jun 30."
The court would resume hearing tomorrow as to whether the plea of Sangma deserves to be heard in detail in the regular course or not.
Earlier, the court had taken on record the short affidavit of Mukherjee, who said the grounds for challenging his election was "ex facie misconceived."
The affidavit said that Mukherjee had resigned from all posts he held before filing nomination for the post of President and it was "absurd" to allege that his signature was forged in the letter for resignation from the post of Chairman of ISI.
Mukherjee said like any other person he has two or three types of signatures which some times reflect his full name and some other time show as PK Mukherjee.
Sangma has contended that Mukherjee was holding offices of profit as chairman ISI, Kolkata and as also the leader of the Congress Party in Lok Sabha when he had entered the Presidential race.
Sangma had also sought a direction for setting aside Mukherjee's election as President and declaring him as elected to the post.