Santhan, Murugan and Perarivalan - all convicted for being part of the group that conspired to kill the former Prime Minister in 1991 - were sentenced to death by the Supreme Court in 1999. Their mercy petitions, filed 11 years ago asking for their sentence to be commuted to life in prison, were rejected earlier this month by President Pratibha Patil.
The convicts have appealed to the High Court against this decision on the grounds that the President's office showed "an inordinate and inexplainable delay" in deciding their mercy petitions violates Article 21 of the Constitution (Protection of life and personal liberty).
"It takes just 30 seconds to take a man from his cell and pronounce him dead. Imagine an 11-year wait," said noted lawyer Ram Jethmalani, who is among those representing the assassins.
The issue has been a politically-loaded one in Tamil Nadu, where Mr Gandhi was killed by an LTTE suicide bomber at an election rally in Sriperumbudur. Inside court, there was thunderous applause when the judges announced that the hanging, meant to take place at Vellore Jail, has been stayed while the case is studied.
This morning, the Tamil Nadu Assembly adopted a unanimous resolution urging President Patil to reconsider the mercy petitions. The resolution was moved by Chief Minister Jayalalithaa, who just yesterday had said that she was powerless to intervene given that the President had ruled out a life sentence. "Many political parties have appealed to me to commute the death sentences and in order to respect the sentiments of the people of the state, I appeal to the members of the House to pass the resolution unanimously," she said.
The Chief Minister was no doubt prompted to change her stand by the open support for the assassins' case stated by her political opponents. Yesterday, her arch rival and DMK chief M Karunanidhi said, "Had young leader Rajiv Gandhi been alive today, that noble man would have definitely come forward to save the lives of Santhan, Perarivalan and Murugan, responding to the voice of true Tamils." In 2000, however, when Mr Karunanidhi was in power, the Tamil Nadu Assembly had recommended the death sentence for the same trio.
In Delhi, Law Minister Salman Khurshid said that the resolution adopted in the Tamil Nadu Assembly is not binding in any way. However, he added that the request will be given serious consideration by the Centre.
Constitutional experts say a court can question the President's decision in this case, though it could set a worrying precedent. "The power of courts is above the executive powers of President. Even after the President has rejected the mercy petition, courts can step in," explained PP Rao. "Not only death convicts, even other criminals would ask for clemency and pardon," said Cho Ramaswamy, political analyst.
Murugan, Santhan and Perarivalan were sentenced to death in 1999, along with Nalini, who is married to Murugan. After Nalini gave birth to a baby girl in jail, her death sentence was commuted to life at the request of Mr Gandhi's wife, Sonia, who is the Congress president. Perarivalan's mother, Arputhammal , who was at court today, broke down. "I was grieving over whether I will get my son back. But Amma (Jayalalithaa) has passed a resolution and has given me joy. She has given me the hope that my son may be saved."