KARACHI, Pakistan -- Last week the world was shocked, and my life was shattered, by the murder of my beloved wife, Mohtarma Benazir Bhutto. Benazir was willing to lay down her life for what she believed in -- for the future of a democratic, moderate, progressive Pakistan. She stood up to dictators and fanatics, those who would distort and defy our constitution and those who would defame the Muslim holy book by violence and terrorism. My pain and the pain of our children is unimaginable. But I feel even worse for a world that will have to move forward without this extraordinary bridge between cultures, religions and traditions.

I married Benazir in 1987 but spent less than five years living with her in the prime minister's house over her two terms in office, which were interrupted by military interventions. I spent more than 11 years in Pakistani jails, imprisoned without a conviction on charges that former prime minister Nawaz Sharif and Pervez Musharraf (who brought and pursued the charges) have now publicly acknowledged were politically motivated. Even before Benazir was first elected prime minister, in 1988, Pakistan's intelligence agencies began working to discredit her, targeting me and several of her friends. I was called "Mr. Ten Percent" by their hired guns in public relations, and the names of her friends abroad were besmirched with ridiculous charges that they headed the nonexistent "Indo-Zionist" lobby.

This campaign of character assassination was possibly the first institutional application of the politics of personal destruction. Benazir was the target, and her husband and friends were the instruments. The purpose was to weaken the case for a democratic government. It is perhaps easier to block the path of democracy by discrediting democratic politicians.

During the years of my wife's governments, she was constrained by a hostile establishment; an interventionist military leadership; a treacherous intelligence network; a fragile coalition government; and a presidential sword of Damocles, constantly threatening to dismiss Parliament. Despite all of this, she was able to introduce free media, make Pakistan one of the 10 most important emerging capital markets in the world, build over 46,000 schools and bring electricity to many villages in our large country. She changed the lives of women in Pakistan and drew attention to the cause of women's rights in the Islamic world. It was a record that she was rightly proud of.

Her murder does not end her vision and must not be allowed to empower her assassins. Those responsible -- within and outside of government -- must be held accountable. I call on the United Nations to commence a thorough investigation of the circumstances, facts and coverup of my wife's murder, modeled on the investigation into the assassination of former Lebanese prime minister Rafiq al-Hariri. And I call on the friends of democracy in the West, in particular the United States and Britain, to endorse the call for such an independent investigation. An investigation conducted by the government of Pakistan will have no credibility, in my country or anywhere else. One does not put the fox in charge of the henhouse.

But it is also time to look forward. In profound sadness, the torch of leadership in the Pakistan People's Party (PPP) has been passed to a new generation, to our son, Bilawal Bhutto Zardari. I will work with him and support him and protect him to the extent possible in the trying times ahead. The Bhutto family has given more than anyone can imagine to the service of our nation, and in these difficult days it is critical that the party remain unified and focused. My wife, always prescient and wise, understood that. Knowing that the future was unpredictable, she recommended that the family keep the party together for the sake of Pakistan. This is what we aim to do.

The Musharraf regime has postponed the elections scheduled for Tuesday not because of any logistical problems but because Musharraf and his "King's Party" know that they were going to be thoroughly rejected at the polls and that the PPP and other pro-democracy parties would win a majority. Democracy in Pakistan can be saved, and extremism and fanaticism contained, only if the elections, when they are held, are free, fair and credible.

To that end, the people of Pakistan must be guaranteed elections that are (1) conducted under a new, neutral caretaker government, free of cronies from Musharraf's party; (2) supervised by an independent and autonomous election commission formed in consultation with the major political parties; (3) monitored by trained international observers who have unfettered access to all polling stations as well as the right to conduct exit polling to verify results; (4) covered by electronic and print media with the freedoms they had before martial law was imposed on Nov. 3; and (5) arbitrated by an independent judiciary as provided for in the constitution. In addition, all political activists, lawyers and judges being detained must be released.

The enemies of democracy and tolerance who took my wife from me and from the world can and must be exposed and marginalized. Dictatorship and fanaticism have always been rejected by the people of Pakistan. If free and fair elections are held, those forces will be defeated again on Feb. 18. And on that day, the vision and indefatigable spirit of Mohtarma Benazir Bhutto will burn brightly, and, in the words of John Kennedy, "the glow from that fire can truly light the world."

Asif Ali Zardari, a former senator, is co-chairman of the Pakistan People's Party with his son, Bilawal Bhutto Zardari.