The destroyers-for-bases deal was an agreement between the United States and the United Kingdom on September 2, 1940, according to which 50 , , and US Navy destroyers were transferred to the Royal Navy from the US Navy in exchange for land rights on British possessions. Generally referred to as the "twelve hundred-ton type" (also known as "flush-deck", or "four-pipers" after their four funnels), the destroyers became the British and were named after towns common to both countries. US President Franklin Roosevelt used an executive agreement, which does not require congressional approval. However, he came under heavy attack from antiwar Americans, who pointed out that the agreement violated the Neutrality Acts. Background By late June 1940, France had surrendered to Germany and Italy. The British and their Commonwealth and empire stood alone in warfare against Hitler and Mussolini. The British Chiefs of Staff Committee concluded in May that if France collapsed, "we do not think we could continue the war with any chance of success" without "full economic and financial support" from the United States. The US government was sympathetic to Britain's plight, but US public opinion then overwhelmingly supported isolationism to avoid involvement in "another European war". Reflecting on that sentiment, the US Congress had passed the Neutrality Acts three years earlier, which banned the shipment or sale of arms from the US to any combatant nation. US President Franklin D. Roosevelt was further constrained by the upcoming 1940 Presidential election, as his critics sought to portray him as being pro-war. Legal advice from the US Justice Department stated that the transaction was legal. By late May, the evacuation of British forces from Dunkirk, France, in Operation Dynamo caused the Royal Navy to need ships immediately, especially as it now fought the Battle of the Atlantic in which German U-boats threatened the British supplies of food and of other resources essential to the war effort. With German troops advancing rapidly into France and many in the US government convinced that the defeat of France and Britain was imminent, the US sent a proposal to London through the British ambassador, the Marquess of Lothian, for an American lease of airfields on Trinidad, Bermuda and Newfoundland. British Prime Minister Winston Churchill initially rejected the offer on May 27 unless Britain received something immediate in return. On June 1, as the defeat of France loomed, Roosevelt bypassed the Neutrality Act by declaring