The Supreme Iraqi Criminal Tribunal will consider charges that Hussein and his co-defendants were involved in ordering a 1982 massacre in a predominantly Shi'ite town north of the capital.
Hussein and his co-defendants will face charges relating to the murders of 140 men and teenage boys in the town of Al-Dujayl. The victims -- mostly Shi'a -- were allegedly executed by secret police following an assassination attempt against the former Iraqi president.
Iraqi prosecutors are expected to try to show the Al-Dujayl incident was part of a pattern of crimes against humanity committed against many Iraqis by Hussein and his regime. Overall, Iraqi and Western human rights groups suspect that Hussein is responsible for at least 300,000 Iraqi deaths in repressive campaigns aimed mostly at Kurds and Shi'a.
Some observers say the prosecution of such crimes requires a massive legal undertaking that the Iraqis are so far poorly equipped to handle. There are concerns that a lack of international assistance has hampered preparation for the trials.
Hanny Megally is an expert with the International Center for Transitional Justice, an independent group that has advised Iraqi officials on how to confront the legacy of repressive rule. He told RFE/RL the decision to launch the trial against Saddam Hussein now was a response to political pressures.
"You could argue [that Iraqi officials] could have waited longer until they were in much better shape, but I think the politics also pushed for them to show that some progress is being made and there is some movement," Megally said. "And, after all, people have been waiting two years and in that sense the pressure mounted."
Hussein and his seven co-defendants are expected to hear the charges against them during the hearing on 19 October, and the court will address procedural matters. The trial is then expected to be adjourned for several weeks. Some believe the court might wait until after elections scheduled for December are held before resuming.
Saddam's defense team said the day before the trial was to open that it will argue that the tribunal does not have the right to try the former Iraqi president. It will present a document showing that the court, organized during the U.S. occupation, does not have jurisdiction to try Saddam Hussein.
Megally said UN opposition to the death penalty, which Iraq has reinstated, as well as security concerns mean the special tribunal lacks some of the expertise available to other war crimes courts.
"Without the UN being the conduit -- and of course because of the death penalty issue, but also because of the security situation -- many internationals have tended to decline the offer to come and help because the only way in to help the court would have been through the auspices of United States and that in itself, I think, was a stumbling block," Megally said.
The United States has played the main advisory role as well as providing most of the funding for the Iraqi court.
White House spokesman Scott McClellan repeated on 18 October that Washington expects the trial to meet international standards, including access to defense counsels and an appeals process.
"This is an Iraqi process, and the Iraqi people will make the decision about how they hold Saddam Hussein to account for his crimes against humanity and his brutalities against the Iraqi people; and they are moving forward on that process tomorrow," McClellan said.
The watchdog group Human Rights Watch has issued a paper criticizing the Iraqi tribunal. It says it has concerns about the tribunal's capacity to hold trials that are fair and "perceived to be fair among the Iraqi population."
Meanwhile, Iran has asked the Iraqi tribunal to also charge Hussein with crimes from the 1980-88 war between the two countries, including the alleged use of chemical weapons.
(By Robert McMahon with contributions from Jeremy Bransten.)
For more on events in Iraq, see RFE/RL's The New Iraq webpage.