VIENNA — In the high-stakes game of political chess underway over the U.S. and U.N. showdown with Iraq, the next move belongs to the scientists.
On Monday and Tuesday, in a austere high-rise building here, Iraqi officials will meet with chief United Nations weapons inspector Hans Blix and Mohammed Baradei, the director of the International Atomic Energy Agency, or IAEA, to discuss the return of the first monitors as early as Oct. 15.
Once they hit the ground, the key to a productive weapons monitoring program in Iraq, say past and present inspectors, will be a simple-sounding phrase: free and unfettered access.
"You can't do effective inspection without access, you have to have the right to go anywhere, any time," said Garry Dillon, who led the IAEA's Iraq inspection team from 1997 to 1999. "If that right is denied, you can't do your job."
It also means access to Iraqi researchers, government officials and documents to figure out how far along the Persian Gulf nation might be in designing and building weapons. Valuable information often comes from face-to-face interviews with scientists.
Without that human intelligence, say former and present inspectors, the international monitors' technical expertise, laboratory analysis and more sophisticated technology are useless.
Next week's meeting here at the IAEA's headquarters, while cloaked in the neutral language of diplomacy and technicalities, will be the first real indicator of Iraq's intentions. If the meetings go well, it could bolster those who argue for delaying military action until the weapons inspectors have a chance to do their job.
The United Nations imposed the weapons inspection program after the 1991 Persian Gulf War to ensure that Iraq was disarmed of any weapons of mass destruction. Iraqi President Saddam Hussein's regime complied to some extent during the 1990s but became increasingly obstructionist before it barred the monitors altogether nearly four years ago.
"The frustrations we had were enormous," said Richard O. Spertzel, the chief U.N. biological weapons inspector from 1994 to 1998.
Information from intelligence sources, scientists, commercial satellites and intercepted procurement efforts suggests to Western officials that Iraq has attempted to revive its three major weapons programs--biological, chemical and nuclear--since 1998.
There is little question that Hussein's regime would try to hide at least some, if not all, of any weapons program it has managed to rebuild. Knowing that, the inspectors say they have tried to map out a plan that would allow them to determine if and when the Iraqis are lying to them and to what degree.
"We are going in well prepared, with a plan, and we never take anything at face value," said Jacques Baute, the Iraq Action Team leader for the IAEA. "We are thorough and suspicious. We expect that the Iraqis have learned lessons from the 1990s and will do things differently. But we will try a few new things as well."
That said, how do the weapons inspectors proceed, what limitations do they face and how successful can they be at finding well-hidden programs?
The last time inspectors were in Iraq, they believe that they uncovered and destroyed much of the country's nuclear weapons program but were less successful at uncovering its biological and chemical weapons stores and labs.
Interviews with people familiar with the inspection program acknowledge that there are particularly daunting obstacles in the biological and chemical fields.
If the inspectors return, there will be two teams. The IAEA includes 15 scientists with expertise in all aspects of nuclear weapon production. The United Nations Monitoring, Verification and Inspection Commission, or UNMOVIC, is responsible for disarming Iraq of any chemical or biological weapons and ballistic missiles with ranges of more than 93 miles.
The two teams coordinate their activities. However, their ability to locate weapons varies widely. Nuclear material leaves what scientists call a "footprint" that can be picked up with the increasingly sensitive equipment available for measuring radioactive substances. Samples of air and water often carry telltale signs.
New X-ray systems for identifying the presence of metals that are characteristic of nuclear substances are now portable. That means inspectors can do analyses in the field and quickly decide whether more thorough follow-up inspections are necessary, said officials at the IAEA.
The chemical and biological lab technology similarly has been miniaturized so that much of it is portable, but biological agents and chemical weapons leave little in the way of footprints.
Iraq is roughly the size of California, and although a full-scale uranium enrichment plant would be hard to hide from a satellite photograph, a lab used for manufacturing the smallpox virus or anthrax could be concealed in a hospital basement. It likely would only be found if someone alerted inspectors to its presence.