After receiving word that he and his International Atomic Energy Agency had won the prestigious award for their efforts to halt the spread of nuclear weapons, ElBaradei said the prize would strengthen his "resolve and those of my colleagues to speak the truth to power".

Judging from the effect the prize has had in the past, the IAEA and ElBaradei could find themselves propelled forward on a great wind of goodwill, but observers caution that the award's effect could also be neutral, or even negative.

"ElBaradei's first comments today were very promising (and) could indicate that this prize will have a very motivating effect," Stein Toennesson, the director of the Peace Research Institute in Oslo, told AFP.

The award could boost the organisation's efforts to ensure that Iran complies with the nuclear non-proliferation treaty and might even lead to an agreement on the issue before the Nobel Prize ceremony is held in Oslo on December 10.

If that happens, "this could turn into a huge success story", Toennesson said.

"But unfortunately it's more likely that the opposite will happen and the conflict (over Iran's nuclear capacities) will escalate," he added.

A number of previous laureates have emerged with stronger resolve, more resources and the international attention needed to get more done, and some have even inspired dramatic political changes.

For Carlos Belo and Jose Ramos-Horta the prize in 1996 brought international attention to the drawn-out and virtually forgotten conflict in East Timor, helping the country achieve independence from Indonesia.

"It is generally agreed that the Nobel Prize has had the greatest impact in East Timor, because it put the question on the international agenda and led to a happy and peaceful ending," Norwegian historian Asle Sveen told AFP.

In other cases, the award has functioned as a protective buffer for prize-winners voicing unpopular opinions under oppressive regimes.

"The most extraordinary effect (of the prize) is when it protects recipients, as in the case of Andrei Sakharov (a Soviet Union dissident honored in 1975) who said the prize had saved his life," Sveen said.

Winning a Nobel in 1983 had also offered protection and an energy-boost to Polish dissident Lech Walesa, who later became Poland's first freely elected president.

Opinions differ on the case of 1991-laureate Aung San Suu Kyi, who has been held in house arrest for more than a decade in connection with her 1990 victory in Myanmar's elections.

Some insist the award has protected her from a worse fate, but others say less international focus might have eased the pressure.

"The prize recognized her as the rightful leader of Myanmar ... This may have contributed to worsening the conflict" there, Toennesson said, pointing out that her opponents may feel they either have to keep the pressure on or allow her to rule the country.

Other Nobel jury picks have been seen as disastrous.

"The main failure came in 1973 with the prize awarded to Henry Kissinger and Le Duc Tho" for reaching a Vietnam ceasefire agreement that soon failed, Sveen said.

That prize, dubbed the Nobel Prize for War by the New York Times, was so controversial that two of the Nobel Committee's five members resigned.

The 1994 prize, awarded to Yitzhak Rabin, Shimon Peres and Yasser Arafat for the now all but shelved Oslo peace accord in the Middle East, also led to the resignation of a committee member.

This year's prize will not be seen as a great success or great disaster, experts said.

"I don't think this year's prize will have a huge impact on its winners," Sveen said.

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