Police and troops had been stationed across Islamabad as the court readied to hear a final appeal in the case of Asia Bibi, who has been on death row since 2010. But one of the three-judge bench, Justice Iqbal Hameed ur Rehman, told the court he had to recuse himself, claiming a conflict of interest.
Taseer, a provincial governor, was gunned down in Islamabad in 2011 after speaking out for Bibi.
His assassin, Mumtaz Qadri, was hanged earlier in 2016.
Rehman was chief justice on the Islamabad High Court which heard Qadri’s appeal in 2011, according to local media.
The Supreme Court did not immediately set a new date for Bibi’s appeal.
Bibi was convicted and sentenced to hang in 2010 after an argument with a Muslim woman over a bowl of water. Her supporters maintain her innocence and insist it was a personal dispute.
But successive appeals have been rejected, and if the Supreme Court bench eventually upholds Bibi’s conviction, her only recourse will be a direct appeal to the president for clemency. If that fails, she could become the first person in Pakistan to be executed for blasphemy.