The verdict of the 17-member apex court bench headed by Chief Justice Iftikhar Muhammad Chaudhury is likely to stir up more turmoil in the country weakening the Presidency further.
Petitions challenging Zardari's eligibility as a presidential candidate are expected to follow from the court's ruling, and about a dozen senior members of Zardari's coterie of advisers will most likely face renewed corruption cases, The New York Times reports.
However, Presidential spokesperson, Farhatullah Babar, stressed both Zardari and the Pakistan People's Party (PPP) respects the court's verdict, and that it would not affect the immunity enjoyed by the President.
Zardari's close aide, Babar Awan, too rebuffed opposition's call for President's resignation, saying he would complete his term in office.
During the hearing, the court raised objections, in particular, over the question of who had authorized the return of 60 million dollars in suspect gains by Zardari to foreign companies in his name after the government withdrew criminal proceedings against him in Switzerland.