Why American accounts overstated Washington treaty success

Have historians overestimated how successful the Washington naval negotiations were for the United States?

Yes; early American confidence weakened at London in 1930 and after closer inspection of Britain's treaty battleships.

Assessments of the Washington conference often inherit the optimism of contemporary American sources. United States officials initially believed they had negotiated an exceptionally successful settlement. Doubts grew during the 1930 London negotiations, when the practical effects of the earlier bargain became clearer. Wartime access to Nelson and Rodney then revealed design choices that showed how effectively Britain had used the treaty rules.