The United Nations decides to impose new, more forceful sanctions against Iran. A dramatic announcement from the Iranian leadership concerning a "major event" is expected. Tehran expels inspectors from the International Atomic Energy Agency, and bars their access to its nuclear sites. It puts its ballistic missiles on a state of alert. The Syrian army is also declaring a state of high alert, and is initiating a large-scale military exercise. Hezbollah Secretary General Hassan Nasrallah rushes to Damascus for a surprise visit. Israel's top intelligence officials convene for an emergency meeting.

They estimate that the sequence of events indicates Iran's intention to announce that it has developed nuclear weapons. Syria and Hezbollah coordinate positions, in anticipation of a possible Israeli or American attack. All parties prepare for war.

This scenario, created by Brig. Gen. Amnon Sofrin, was sketched to illustrate the complexity of seeing the "intelligence picture."

Sofrin will present the scenario tomorrow at an international conference on security, defense and intelligence that will involve hundreds of participants from dozens of countries; the event is sponsored by International Security and Defence Systems Ltd., a private company headed by Leo Gleser.

Two and a half years ago, Sofrin completed his term as head of the Mossad's intelligence directorate, and today he works as a private consultant on security matters. In 2003, he was recruited by Mossad chief Meir Dagan.

Before his work with the Israeli spy agency, he held a number of intelligence roles for the Israel Defense Forces, including stints as the Central Command's intelligence officer and commander of the IDF land forces' intelligence and reconnaissance center.

Though his lecture will be theoretical, Sofrin believes his intelligence assessments should be taken seriously, as a result of his past experience, particularly his five years of service as head of the Mossad's intelligence directorate.

That directorate consists of a number of units, including a research division and a unit responsible for prioritizing and evaluating information. The directorate restructuring was undertaken by then-Mossad Director Efraim Halevy in response to the botched attempted assassination of Hamas leader Khaled Meshal in Jordan in 1997.

During Dagan's term, the directorate underwent some additional alterations. According to foreign sources, during the years of Sofrin's service, the Mossad carried out some notably successful operations that made a significant strategic contribution to Israel's security. Two particularly conspicuous operations were the air attack on the nuclear reactor in Syria in 2007, and the assassination of Hezbollah master terrorist Imad Mughniyeh in February 2008, in Damascus, both of which Israel has declined to take responsibility for. It can be assumed that there are other Mossad operations unknown to the public; and the organization has in recent years also invested considerable effort in the arduous task of gathering information about Iran's nuclear program.

Without exposing secrets, it can also be assumed that the Mossad's intelligence directorate made invaluable contributions to Mossad operations. Sofrin refuses to discuss his Mossad work, and is especially reticent about operations in which Israel has never admitted involvement.

In a discussion with Haaretz, Sofrin emphasized that intelligence goes beyond the collection of information - the process of evaluating the information is also complicated and crucial.

The scenario sketched above about regional preparedness for war can be interpreted in different ways, Sofrin notes; Iran doesn't necessarily have nuclear weapons, but is instead attempting to deter any aggression.

The Syrian army movements could be part of a routine, annual training exercise; and Nasrallah might, on this alternative scenario, be traveling to Damascus to coordinate the continued flow of weapons.

"Intelligence," Sofrin said, "is not designed to serve itself, but is rather a tool that supports the decision making process. As a first step, a coherent intelligence picture must be formed. The problem is that in the case of most intelligence assessments, the available information is imperfect. Only 50-60 percent of the intelligence picture is based on solid information, and the remainder comes from assessment and interpretation."

Sofrin explains that intelligence evaluation derives from experience and accumulated knowledge; such assessments are not foolproof, and can result in error.

"The history of intelligence is the history of misinterpretations and errors," he said.

After information is collected and a senior intelligence officer fills in holes by making assessments, the officer needs to confer with decision makers. Sofrin was involved in many such consultations.

He briefed prime ministers and government ministers, took part in cabinet meetings and various secret deliberations; in such forums, he delivered the Mossad's intelligence assessments. Not all decision makers were cognizant of nuances and details related to the evaluation and prioritization of intelligence materials and the finalization of an intelligence assessment and some would demand concrete answers. Sometimes the politicians drew conclusions that differed from assessments reached by officials in the intelligence community.

Under opaque circumstances, decision-makers, like the public itself, deal with confusion, and have trouble accepting the fact that "intelligence leaves question marks," as Sofrin phrases it.

In many instances, he said, "intelligence does not solve the problem."

Sofrin acknowledged that people harbor "great expectations concerning intelligence officials, and think that we are magicians. There is a myth in the Israeli public that intelligence is omnipotent. You have to take into account that we operate in a difficult region. We have to prioritize, and that means taking risks - in fact, intelligence work is, to some extent, risk-taking."

All told, Sofrin concluded, "without belittling the work done by others, I have no doubt that Israeli intelligence is superior in terms of understanding the region of the Middle East, and obtaining information about it."