A railroad was completed across Panama in 1855, but no canal was constructed until years after the great transcontinental railroads had bound California to the East by bonds which required no foreign sanction.

Yet the Clayton-Bulwer Treaty remained an entangling alliance, destined to give lovers of peace and amity many more uncomfortable hours.
During the Civil War other causes of irritation arose between the United States and Great Britain.

The proclamation of neutrality, by which the British Government recognized the Confederacy as a belligerent, seemed to the North an unfriendly act.

Early in the war occurred the Trent affair, which added to the growing resentment.

* It was held to be a violation of professed neutrality that Confederate commerce destroyers were permitted to be built and fitted out in British yards.