How he handles the reinstatement of judges dismissed by Musharraf last year will go some way to determining his credibility, as he has stalled on the issue so far.
Sharif, the prime minister who was overthrown by Musharraf, pulled his Pakistan Muslim League (Nawaz) (PML-N) party out of the coalition because of Zardari's stalling on the question of the judiciary, just days after his usurper quit.
Eyes are now on Punjab, Pakistan's richest province, to see if Zardari tries to destabilise a PML-N provincial government.