Both nations were to guarantee this neutrality, and other nations were invited to join with them.

No other nations did join, however, and the project became a dual affair which, owing to the superiority of the British Navy, gave Britain the advantage, or would eventually have done so if a canal had been constructed.

Subsequently the majority of Americans decided that such a canal must be under the sole control of the United States, and the treaty then stood as a stumbling block in the way of the realization of this idea.
More immediately important, however, and a great wrench to American policies, was the provision that neither power "will ever erect or maintain any fortifications commanding" the canal "or occupy, or fortify, or colonize, or assume or exercise any dominion over...

any part of Central America." This condition violated Adams's principle that the United States was not on the same footing with any European power in American affairs and should not be bound by any self-denying ordinance, and actually it reversed the principle against the United States.

An explanatory note accompanying the treaty recognized that this provision did not apply to Belize and her dependencies, and Great Britain promptly denied that it applied to any rights she already possessed in Central America, including the Mosquito protectorate and certain Bay Islands which were claimed by Great Britain as dependencies of Belize and by Honduras as a part of her territory.
In vain did Webster, who succeeded Clayton, seek an agreement.