When the Treaty on the Non-Proliferation of Nuclear Weapons was proposed, there were predictions of 25–30 nuclear weapon states within 20 years. How reliable were these predictions and which were the leading candidate countries to acquire nuclear weapons ?

by Avinash_Sharma

I came across the prediction on the Wikipedia page of NPT

At the time the NPT was proposed, there were predictions of 25–30 nuclear weapon states within 20 years. Instead, over forty years later, five states are not parties to the NPT, and they include the only four additional states believed to possess nuclear weapons.

1st line, 5th paragraph.

I realise Wikipedia can be unreliable, but I was just curious about such a bold prediction.

restricteddata

The numbers refer to classified estimates that were made in the early 1960s as part of the Kennedy administration. Robert McNamara's 1963 estimates have been declassified. You can read it for the methodology and results. There is a nice table on page 6. Some notable countries they thought likely to develop weapons without an NPT include West Germany, Israel, Egypt (UAR), China. Countries that would have the capability to develop weapons but low incentive to do so included Canada, Japan, Sweden, and India.

There are other estimates that were made in the 1960s. It is obviously a rather imprecise thing — you have to estimate both the technical capability and the political will, as well as anticipate whether countries would help others to proliferate (e.g., in 1966 Pakistan was judged as a potential proliferator, but only with outside help — and indeed, they received information through espionage from the Dutch uranium enrichment program, and also received considerable aid from the Chinese).

This article does a nice job of laying out some of the estimates that were floating around at the time.

As for "reliability" — it is very hard to gauge that. Most of these states did not proliferate. Some did. Would things have been different without the NPT? That's a very tough counterfactual, because the NPT created a strong framework for both monitoring work and demanding that weapons work be avoided. Some of these estimates did fail to identify some potential proliferators (South Africa and Taiwan were not in some of the earlier ones, and they both had nuclear programs, although Taiwan's was not successful), which is perhaps evidence of unreliability. But it is hard to say in something as complex as this what would have happened without the NPT — aside from the case-by-case nature of proliferation, the NPT also is argued to have established "international norms" which is a much vaguer thing to measure (though that doesn't mean they don't exist).

In terms of the raw numbers, those estimates don't say 25-30 nations — which is an awful lot. They are more on the order of 5-10 problematic nations. But the belief was then, as it is now, that local nuclear acquisition could launch local proliferation races as well (e.g., if Brazil got a nuke, Argentina would have to get one too, and vice versa) so any proliferating state is (under this theory) a catalyst for further proliferation.