Now, if the American fleet is in a position to prevent access to the American coast and to the Gulf of Mexico, its adversaries may have the most powerful battleships in their naval bases and the most imposing reserves of motor-lorries and aeroplanes in their depots, yet all these forces, in the present state of oil production, run the risk of being paralysed for want of sufficient supplies.[35] But the United States are not content with wanting to deprive Britain of her naval supremacy. By threatening reprisals on their territory against the _Royal Dutch-Shell_ and British companies, they compelled the British Government to give way on questions concerning Palestine and Mesopotamia. The Americans were all the more furious to see their prospectors arrested in Palestine, because they had obtained the right to make borings there, before the War, from the Turkish Government. The whole of the valley of Yarmak, the neighbourhood of Bethlehem (Vebi Musa), the south of the Dead Sea, and the east of the Jordan, were to be prospected by the _Standard_.[36] Moreover, by the General Leasing Act of 1920, the Federal Government obtained authority to exact from every oil company operating in the United States, that it should number none but American citizens among its shareholders. A judicial decision has just been given, refusing to British citizens the right to become shareholders in a company of this kind. Moreover, Mr. Daniels, Secretary of the Navy, wished to get a Bill passed through Congress, authorizing the President to place an embargo on the export of petroleum. The _Royal Dutch-Shell_, which now draws 43 per cent. of its output from the United States, would thus be unable to transport it to Great Britain. But on this point he is in conflict with Mr. Payne, the new Secretary of the Interior, who thinks the above-mentioned Bill a sufficient protection for the United States. This Bill forbids the leasing of wells by a corporation of foreign shareholders, unless these latter belong to a country which grants reciprocal treatment; the corporation, besides, must have a majority of foreign shareholders. The system of reciprocity was inaugurated by President Harding. Governments which allow free competition to American companies receive the like treatment. The permits solicited by the _Royal Dutch_ will therefore probably be refused, while those sought by Canadian companies, such as the _Midland Oil_, are much more likely to be granted; it will be enough that their British shareholders become Canadians. For Canada has always allowed the _Standard Oil_ very great liberty on her territory. In April 1919, she even refused the association of interests proposed by the _Shell_, for fear of offending Washington. If ever war broke out between Great Britain and the United States, Canada would almost certainly proclaim her independence and break away from the British Empire.