Kaira and senior PPP leaders Jahangir Badar and Raja Parvez Ashraf addressed the news conference hours after a three-judge bench headed by Chief Justice Iftikhar Chaudhry disqualified Gilani in response to several petitions that had challenged National Assembly Speaker Fehmida Mirza's decision not to disqualify the premier following his conviction of contempt.
The bench ruled that the post of premier had been vacant since April 26, when another seven-judge bench had convicted Gilani of contempt for refusing to reopen graft cases in Switzerland against Zardari.
In response to a question, Kaira said, "Technically, after the court's verdict, the prime minister is no longer the prime minister...if there is no prime minister, the cabinet doesn't exist".
Referring to the PPP's call for its workers to remain calm, Kaira said Punjab was witnessed widespread protests against power outages that were being "sponsored" by provincial government of the opposition Pakistan Muslim League-N.
"People are being killed and property is being destroyed, and the provincial government has called for revolution against the centre. We fear there could be a civil war if the PPP too calls for protests," Kaira said.
PPP sources said the party had called a meeting of leaders of the ruling coalition tonight and a meet of the PPP parliamentary party tomorrow to choose a candidate to replace Gilani.
However, Kaira and Badar said the PPP would decide its future course of action after consulting its legal experts and coalition partners.
"The CEC has given all its powers to party co-chairman Zardari to decide the future course of action," Badar said.
The PPP's leadership has not discussed any proposal on seeking a presidential pardon for Gilani, he added.