This Reporter's Notebook was written by CBS News chief foreign correspondent Lara Logan.
There is a moment when you realize that no matter what the consequences, you have stumbled across a story that must be told. That is how it was when I first heard that Sunni people were too terrified to go to hospitals in Baghdad because they might be targeted and killed by .
This is the most cynical example I've encountered of how sectarian violence is destroying Iraq's people.
Not just because patients have been murdered and their family members followed and executed, but because people in need are being denied their most basic human right: to seek medical care.
Ironically, the people who risked their lives to help me tell this story of how medical institutions have been turned into instruments of sectarian slaughter against Sunnis, are all Shiites. Because, as decent human beings, they do not want such acts committed in their name. They do not want the blood of their neighbors and friends on their hands. And they want the killing to stop.
The problem each of them faces is that if, or when, the situation here disintegrates into all-out war, they will no longer have the luxury of principle and choice: they will be forced to ally with their own kind for their survival. And the same can be said for the Sunnis, who are being pushed towards the terrorist organization of al-Qaeda in Iraq, with whom they have absolutely no affinity.
So a country - in which millions of families are made up of both Sunni and Shia - is carving a new chapter of division in its history, written in the blood of innocent people.
What has happened to Baghdad's hospitals is symbolic of what has happened to the entire country. Parties, supported by their armed militias, have taken over the functions of government. The police force and army are not the only institutions that have been infiltrated; the problem extends far beyond - to the very fabric of society.
Sunnis are afraid to apply for passports because they have to go through the Shiite-run Ministry of Interior, which can then trace them and have them killed.
When we went to interview the Minister of Health, we found yellow collection boxes for the Shiite party he belongs to in the grounds of the ministry and at the entrances. Yellow boxes covered in Arabic scrawl, calling on people to contribute to Moqtada al Sadr, the founder and leader of the Mahdi Army milita.
No wonder people associate anything good coming from the ministry with Sadr and credit the Iraqi government with nothing. Parties, and not the government, rule Iraq now - to the extent that Sunnis in Baghdad are too afraid to go to the morgue to collect the bodies of their loved ones because they are being watched and know they could be followed, kidnapped and murdered.
Even Sadr's Health Minister acknowledges that this is happening. What he denies is that the Mahdi Army are the people responsible.
So the bodies in Baghdad's main morgue keep piling up, five filling a space normally occupied by one. And the trucks keep coming, every two to three days, loading up the overflow and shipping them south to be buried in mass graves with no names, only a number. Four months ago, the "cemetery for the unknown" in the southern Shiite city of Kerbala did not even exist; now, there are more than nine hundred unclaimed bodies resting in that dusty ground.
Watching the men wrap the bodies and pray over them, I was struck by how systematic and organized the whole process is. Even in the midst of the madness and the frenzy of bloodletting, there are still rules to be followed, and procedures to carry out. So the bodies are numbered, photographed and records of the slaughter are kept.