The lawsuit filed by Sikhs For Justice (SFJ) accuses Sonia Gandhi of shielding, protecting and rewarding the perpetrators of violence against Sikhs in November 1984 in the aftermath of assassination of then Prime Minister Indira Gandhi.
The court is set to hear the oral arguments on whether the 1984 claims are barred under US Supreme Court case Kiobel v. Royal Dutch Petroleum.
It would also hear arguments on if two individuals Jasbir Singh and Mohender Singh are proper plaintiffs on behalf of their family members and whether rights group has associational standing to file the lawsuit.
In June 2014, a federal judge dismissed the lawsuit against Sonia Gandhi ruling that she is not liable under Torture Victims Protection Act (TVPA) and that the plaintiffs have no standing to bring the lawsuit.
In their appeal, SFJ and 1984 victims invoked the principle of international law that "those who cover up a crime are just as guilty as the ones who commit it".
The allegations against Sonia Gandhi includes shielding and protecting Kamal Nath, Jagdish Tytler, Sajjan Kumar and other Congress party leaders.
"We have a strong argument that US Supreme Court's decision in Kiobel v. Royal Dutch Petroleum does not bar the law suit against human rights violators when the victims have no other recourse," said SFJ legal advisor Gurpatwant Singh Pannun.
In September 2013, a class action suit was filed against Sonia Gandhi by SFJ and victims of 1984 under Alien Tort Claims Act (ATCA) and Torture Victim Protection Act (TVPA).