FORMER Pakistani Premier Benazir Bhutto may not be a spent political force. But her political fortunes are flagging, Pakistani analysts say.Since being pushed from power almost a year ago, the leader and her Pakistan People's Party (PPP) have taken a beating. Mrs. Bhutto and senior associates face corruption charges and possible disqualification from politics. For her flamboyant husband, Asif Ali Zardari, it's worse. Jailed since last fall, Mr. Zardari is charged with abetting a London-based Pakistani businessman and extorting a huge ransom. If convicted, he could face the death penalty. Bhutto's attachment to the controversial Zardari and her obsession with freeing him is undermining her leadership of the PPP and her political future, analysts and party loyalists say. "She's become unhinged," says an analyst close to Bhutto. Her father, former Prime Minister Zulfikar Ali Bhutto, was executed and her younger brother died under mysterious circumstances. "The party has a lot of residual strength. But if she continues, she will dissipate her strength completely and her party will be even more demoralized than it already is." Meanwhile, the party is reeling from a massive clampdown in Sindh where Chief Minister Jam Sedeq Ali, an ally of President Ghulam Ishaq Khan, seeks to crush the party. Bhutto has been widely criticized for her long absences while her party has been under attack. Recently she took a three-week tour of Europe and Northern Africa, leaving her party officials to protest a new law suspending legal rights. For his part, Sharif, with whom Bhutto skirmished during her 20 stormy months in power, worries that disqualifying his rival and convicting her husband could unleash the Bhutto charisma and street power. Instead, he wants to sideline her and woo members of her party as he builds his political strength, observers say. "Benazir and the PPP are under siege," says a Western diplomat.