Let us pray that her legacy will be a brighter, more hopeful future for the people she loved and the country she served. My family and I extend our condolences and deepest sympathies to the victims and their families and to the people of Pakistan.

Senator Barack Obama: I am shocked and saddened by the death of Benazir Bhutto in this terrorist atrocity. She was a respected and resilient advocate for the democratic aspirations of the Pakistani people. We join with them in mourning her loss, and stand with them in their quest for democracy and against the terrorists who threaten the common security of the world.

John Edwards: Benazir Bhutto was a brave and historic leader for Pakistan. Her assassination is a sad and solemn event, and our hearts go out to her family and to the Pakistani people. But we will not let this contemptible, cowardly act delay the march of progress in Pakistan for a single second.

I have seen firsthand in Pakistan, and in meetings with Prime Minister Bhutto and President Musharraf, the instability of the country and the complexity of the challenges they face.  At this critical moment, America must convey both strength and principle. We should do everything in our power to help bring the perpetrators of this heinous act to justice and to ensure that Bhutto's movement toward democracy continues.

Senator Joe Biden: This is a terrible day. My heart goes out to Benazir Bhutto's family, friends and followers.

Like her father before her, Benazir Bhutto worked her whole life � and gave her life � to help Pakistan become a democratic, secular and modern Muslim country. She was a woman of extraordinary courage who returned to Pakistan in the face of death threats and even after an assassination attempt the day of her return, she did not flinch. It was a privilege to know her these many years and to call her a friend.

I am convinced Ms Bhutto would have won free and fair elections next month. The fact that she was by far Pakistan's most popular leader underscores the fact that there is a vast, moderate majority in Pakistan that must have a clear voice in the system. Her assassination makes it all the more urgent that Pakistan return to a democratic path.

This fall, I twice urged President Musharraf to provide better security for Ms Bhutto and other political leaders � I wrote to him before her return and after the first assassination attempt in October. The failure to protect Ms Bhutto raises a lot of hard questions for the government and security services that must be answered.

I know that Benazir's followers will be tempted to lash out in anger and violence. I urge them to remain calm � and not play into the hands of the forces of destruction. I urge Pakistan's leaders to open a fully accountable and transparent investigation. We must find out who was behind this and bring those responsible to justice. And the United States should offer any assistance necessary, including investigative teams, to get to the bottom of this horror.

The way to honor Benazir Bhutto is to uphold the values for which she gave her life: democracy, moderation and social justice. I join with the Pakistani people in mourning the loss of a dear friend.

New Mexico Governor Bill Richardson: Benazir Bhutto was a courageous woman. Her death, and the deaths of so many of her supporters, is more than just a tragedy. It is a testament to the will of the Pakistani people to see democracy restored. My thoughts and prayers are with the families of those who died today.

Senator Chris Dodd: Today's news from Pakistan is both shocking and saddening. As a member of the Foreign Relations Committee, I have had the opportunity to travel to Pakistan and come to know former prime minister Bhutto very well over the years. I spoke to her personally several weeks ago and have stayed in close contact with her since. She was a respected leader who played an important part in moving Pakistan toward democracy.

As we recognize the loss of a leader today, we must also recognize the implication of today's tragedy to the security of the region and to that of the United States.

At this critical time we must do everything in our power to help Pakistan continue the path toward democracy and full elections. Our first priority must be to ensure stability in this critical nuclear state.

The United States should also stand ready to provide assistance in investigating this heinous act. And as Pakistan [tries to bring the] perpetrators to justice, it should also demonstrate that it will not allow such violence to derail democracy and proceed with elections in a timely manner.

US Representative Dennis Kucinich: This is a very dangerous moment for the world. Prime Minister Bhutto represented the forces of reform and the hope for an end to repression in a troubled region, and her death is a major loss to those efforts.

This terrible tragedy also underscores the need for the United States to adopt a new foreign policy toward the entire region because our current policy is all wrong. Our interference in the internal affairs of Pakistan has opened wide the doors of repression and violence. At this very moment, we should be working with leaders of the region to convene a meeting at the highest levels to begin a new effort towards stabilization and peace.

The United States must take a new direction in Pakistan and throughout the region. I met Bhutto several times, both in Washington and New York. She was deeply and genuinely dedicated to Pakistan. This is a tragic loss.

Rudy Giuliani: I was deeply saddened today to learn about the death of Pakistani opposition leader Benazir Bhutto. My deepest condolences go out to the family and supporters of this remarkable woman, an individual who paid the ultimate price for her embrace of moderation and rejection of extremism.

The death of Benazir Bhutto underscores yet again the grave dangers we face in the world today and particularly in countries like Pakistan, where the forces of moderation are arrayed in a fierce battle against those who embrace violent Islamic extremism.

Given Pakistan's strategic location, the international terrorist groups that operate from its soil, and its nuclear arsenal, the future of that country has deep implications for the security of the United States and its allies. America must stand on the right side of this ongoing struggle.

The assassination of Benazir Bhutto is a tragic event for Pakistan and for democracy in Pakistan. Her murderers must be brought to justice and Pakistan must continue the path back to democracy and the rule of law. Her death is a reminder that terrorism anywhere � whether in New York, London [Images], Tel-Aviv or Rawalpindi � is an enemy of freedom. We must redouble our efforts to win the terrorists' war on us.

Former Massachusetts governor Mitt Romney: This is a stark reminder that America must not only stay on high alert, but remain actively engaged across the globe. Pakistan has long been a key part in the war against extremism and radical jihadists. For those who think Iraq is the sole front in the War on Terror, one must look no further than what has happened today. America must show its commitment to stand with all moderate forces across the Islamic world and together face the defining challenge of our generation � the struggle against violent, radical jihadists.
At this difficult time, our thoughts and prayers go to the family of Benazir Bhutto, and to all the people of Pakistan who are fighting against extremist forces that would commit such heinous acts as the whole world has witnessed today.

Former governor of Arkansas Mike Huckabee: I am deeply troubled by the news accounts this morning of Pakistani opposition leader and former prime minister Benazir Bhutto's assassination in a suicide attack. This is devastating news for the people of Pakistan, and my prayers go out to them as we follow developments regarding this dire situation.

The terrible violence surrounding Pakistan's upcoming election stands in stark contrast to the peaceful transition of power that we embrace in our country through our Constitution. On this sad day, we are reminded that while our democracy has flaws, it stands as a shining beacon of hope for nations and people around the world who seek peace and opportunity through self-government.

Benazir Bhutto's assassination should also stand as a stark reminder for those who doubt the nature of our enemy.

I believe that we are currently engaged in a world war. Radical Islamic fascists have declared war on our country and our way of life. They have sworn to annihilate each of us who believe in a free society, all in the name of a perversion of religion and an impersonal god. We go to great extremes to save lives, they go to great extremes to take them. This war is not a conventional war, and these terrorists are not a conventional enemy. We must fight the war on terror with the intensity and single-mindedness that it deserves.

Senator John McCain: In my numerous visits to Pakistan - to Islamabad, to Peshawar, even to the tribal areas of Waziristan - I have seen first hand the many challenges that face the political leadership there, challenges so graphically portrayed by today's tragedy. There are, in Pakistan, brave individuals who seek to lead their country away from extremism and instability and into the light of a better day. America, I believe, must do all we can to support them.

Fred Thompson, in an interview with Fox News: It is a tragedy, of course. It reminds us that things can happen in faraway places of the world that can affect the United States. I think this should be of great concern to us. It is almost a perfect storm in a very bad sense because two forces are operating against each other that are both desirable. One is democracy: they were making progress in that regard in that country. Former prime minister Bhutto was an important part of that process. But the other is stability. Pakistan is a nuclear country, and we cannot afford to let nukes fall into the hands of dangerous Muslim radicals. We are hoping those two things can be balanced out. We can see the continued progress toward a democratic society but also maintain stability in the country, which seems to be very much in doubt right now.