How effective was the IAEA?

Here is the Open AI call for international regulation, most of all along the lines of the International Atomic Energy Agency.  I am not in general opposed to this approach, but I think it requires very strong bilateral supplements, from the United States of course.  Which in turn requires U.S. supremacy in the area, as was the case with nuclear weapons.  From a 564 pp. official work on the topic:

For nearly forty years after its birth in 1957 the IAEA remained essentially irrelevant to the nuclear arms race. (p.22)

There is also this:

However, in the late 1950s and early 1960s it was not the failure of the IAEA’s functions as a ‘pool’ or ‘bank’ or supplier of nuclear material that inflicted the most serious blow on the organization, on its safeguards operation and eventually on Cole himself. For a variety of reasons, the Agency’s chief patron, the USA, chose to arrange nuclear supplies bilaterally rather than through the IAEA. One reason was that the IAEA had been unable to develop an effective safeguards system. Another was that in a bilateral arrangement it was the US Administration, under the watchful eyes of Congress, that chose the bilateral partner rather than leaving the choice to an international organization that would have to respond to the needs of any Member State whatever its political system, persuasion or alliance. But the most serious setback came in 1958 when, for overriding political reasons, the USA chose the bilateral route in accepting the safeguards of EURATOM as equivalent to — in other words as an acceptable substitute for — those of the IAEA.

It is frequently suggested that the IAEA has been partially captured by the nuclear sector itself.  I do not consider that bad news, but it is a sobering thought for those expecting too much from this approach.  Do note that it took years to set up the agency, and furthermore when North Korea wanted to acquire nuclear weapons the country simply left the agency and broke its earlier agreement.  Perhaps the greatest gain from this approach is that the non-crazy nations have a systematic multilateral framework to work within, should they decide to defer to the external, bilateral pressure from the United States?

On the other side, my fear is that the international agreement will lead to excess regulation at the domestic level.

There is also this:

The fact that Iraq’s nuclear weapon programme had been under way for several years, perhaps a decade, without being detected by the IAEA, led to sharp criticism of the Agency and posed the most serious threat to the credibility of its safeguards since they had first been applied some 30 years earlier.

All of these issues could use much more intelligent discussion.