Grey gave a great push to convince his colleagues to consult the French government about activating the House-Grey Memorandum, only to be outmanoeuvred. With this diplomatic alternative set aside, the military successfully pressured the government to assent to a major summer offensive on the Somme. The military also sought to replace the strategy agreed a few months earlier with an economic fantasy: the military was now looking to win the war with an offensive in 1917 instead of in 1916, but refused to accept that Britain would face serious financial problems in continuing the Allies' massive US supplies through a 1917 campaign. Despite fierce resistance within the Cabinet, the House of Commons forced the acceptance of the military's position. The British government suffered a financial scare when McKenna warned that their assets deployable in the United States faced exhaustion by autumn. McKenna was wrong about the timing: Britain had more assets than he thought, enough to last them into early 1917. But the scare resulted in a serious reconsideration of the House-Grey Memorandum when House and Wilson pushed for an autumn implementation of the agreement. The memorandum's proponents were unintentionally undermined by Wilson’s speech to the US League to Enforce Peace.

Britain's great gamble began with the launch of the Somme Offensive. To extend their American assets, Asquith dislodged the spendthrift Lloyd George from the Ministry of Munitions by promoting him to War Secretary, replacing him with the more economy-minded Edwin Montagu. Startling talk of peace came from French President Raymond Poincaré, which British hardliners moved rapidly to bury. Otherwise, the question of American mediation only rumbled very quietly beneath the surface. British intelligence opened a new source of information with the discovery of the "Swedish Roundabout", unlocking the communications of the German Ambassador to the United States. The British military leadership continually reassured the government that the Somme Offensive was making great headway. As Romania moved to enter the war on the Allied side in August, the government was taken to unfamiliar heights of optimism: it finally seemed as if the Allies might be able to win the war on schedule.