This restrictive policy, which touched the American pocket and consequently the American heart so deeply, was complicated by another question of equal, if not greater, import.  The forcible impressment of men to man the British fleet had been for many years a necessary evil in view of the national emergency, and of the increase in the mercantile marine which attracted large numbers to its service.  Great abuses were perpetrated in the operation of this harsh method of maintaining an efficient naval force, and there was no part of the British Isles where the presence of a press gang did not bring dismay into many a home.  Great Britain, then and for many years later, upheld to an extreme degree the doctrine of perpetual allegiance; she refused to recognise the right of any of her citizens to divest themselves of their national fealty and become by naturalisation the subject of a foreign power or a citizen of the United States Such a doctrine was necessarily most obnoxious to the government and people of a new republic like the United States, whose future development rested on the basis of a steady and large immigration, which lost much of its strength and usefulness as long as the men who came into the country were not recognised as American citizens at home and abroad.  Great Britain claimed the right, as a corollary of this doctrine of indefeasible allegiance, to search the neutral ships of the United States during the war with France, to enquire into the nationality of the seaman on board of those vessels, to impress all those whom her officers had reason to consider British subjects by birth, and to pay no respect to the fact that they may have been naturalised in the country of their adoption.  The assertion of the right to search a neutral vessel and to impress seamen who were British subjects has in these modern times been condemned as a breach of the sound principle, that a right of search can only be properly exercised in the case of a neutral’s violation of his neutrality—­that is to say, the giving of aid to one of the parties to the war The forcible abduction of a seaman under the circumstances stated was simply an unwarrantable attempt to enforce municipal law on board a neutral vessel, which was in effect foreign territory, to be regarded as sacred and inviolate except in a case where it was brought under the operation of a recognised doctrine of international law.  Great Britain at that critical period of her national existence would not look beyond the fact that the acts of the United States as a neutral were most antagonistic to the energetic efforts she was making to maintain her naval supremacy during the European crisis created by Napoleon’s ambitious designs.