Marblehead schooner. Such a principle, however convenient to Great Britain, was not suited to the interests of New England shippers. In peace their chances were comparatively few, and the chief diplomatic difficulties between European governments and the United States had their source in the American attempt to obtain legal recognition of trade which America wished to maintain with the colonies; but in war the situation changed, and more serious disputes occurred. Then the French and Spanish West Indian ports were necessarily thrown open to neutral commerce, because their own ships were driven from the ocean by the superiority of the British navy. Besides the standing controversy about the admission of American produce to British islands, the British government found itself harassed by doubts to what extent it might safely admit the Americans into the French or Spanish West Indies, and allow them to carry French property, as though their flag were competent to protect whatever was under it. Granting that an article like French sugar might be carried in a neutral vessel, there were still other articles, called contraband, which ought not to be made objects of neutral commerce; and England was obliged to define the nature of contraband. She was also forced to make free use of the right of blockade. These delicate questions were embittered by another and more serious quarrel. The European belligerents claimed the right to the military service of their subjects, and there was no doubt that their right was perfect. In pursuance of the claim they insisted upon taking their seamen from American merchant-vessels wherever met on the high seas. So far as France was concerned, the annoyance was slight; but the identity of race made the practice extremely troublesome as concerned England.