The war fell into a long stalemate with very high casualties on the Western Front in France. Both sides rejected offers by Wilson and House to mediate an end the conflict.[158] From 1914 until early 1917, Wilson's primary foreign policy objectives were to keep the United States out of the war in Europe and to broker a peace agreement.[159] He insisted that all U.S. government actions be neutral, stating that Americans "must be impartial in thought as well as in action, must put a curb upon our sentiments as well as upon every transaction that might be construed as a preference of one party to the struggle before another."[160] As a neutral power, the U.S. insisted on its right to trade with both sides. However the powerful British Royal Navy imposed a blockade of Germany. To appease Washington, London agreed to continue purchasing certain major American commodities such as cotton at pre-war prices, and in the event an American merchant vessel was caught with contraband, the Royal Navy was under orders to buy the entire cargo and release the vessel.[161] Wilson passively accepted this situation.