A year later, after fruitless negotiations, the German government announced to the United States that it proposed, in conjunction with Great Britain and Italy, to establish a pacific blockade of Venezuelan harbors. The United States replied that it did not recognize a pacific blockade which adversely affected the rights of third parties as a valid proceeding. The powers then proposed to establish a "warlike blockade," but "without any declaration of war." This device was resorted to at the suggestion of the German government, in order to avoid a formal declaration of war, which could not be made without the consent of the Bundesrath. Meanwhile, Venezuela's gunboats had been seized and her ports blockaded, acts which Mr. Balfour admitted on the floor of the House of Commons constituted a state of war; and on December 20 a formal blockade was announced in accordance with the law of nations, which created a status of belligerency.[250] The hostilities thus commenced were brought to a close by the diplomatic intervention of the United States. Acting under instructions from Washington, the American minister Herbert W. Bowen succeeded in persuading Venezuela to recognize in principle the claims of the foreign powers and to refer them to mixed commissions for the purpose of determining the amounts.[251] Great Britain and Italy agreed to this arrangement, but the German Kaiser remained for a time obdurate. What followed Germany's refusal to arbitrate is described in Thayer's "Life and Letters of John Hay" in the following words: