During December 1916, President Woodrow Wilson received word from the non-militaristic elements in the German government that they would be open to peace talks since the British blockade was starting to have a serious effect on the food supply for German civilians; it was the first chink in the German armor. As far as Colonel House (Wilson's representative in Europe) was concerned, Britain was the only obstacle to peace in Europe. Germany and Britain wanted commercial advantages from the US but neither nation offered anything in return in terms of peaceful overtures. By then Wilson believed that only he alone could (and should) speak for not only the US, but for the world as well. Wilson hoped to propose a series of terms that would deliver an enduring peace; as far as Wilson was concerned, he was the foreign policy of the US. On 3 January 1917, Wilson and House started to create their plan to remake the world, starting with the principle of self-determination.
On 31 January 1917, Germany announced a new naval engagement policy of unrestricted submarine warfare, which stated that any ship in a war zone could be attacked, even ships from neutral nations. On 3 February 1917, Wilson announced that diplomatic ties with Germany had been severed, and that the German Ambassador to the US had been expelled; the US was now only one step away from declaring war on Germany. On 29 February 1917 came news of the Zimmermann Telegram. The British had intercepted the coded telegram on US wires weeks before but didn't relay what it held to Wilson until 25 February 1917. Wilson soon thereafter again addressed Congress, again pushing for "armed neutrality".
On 5 March 1917, Wilson delivered his Second Inaugural Address (4 March was on Sunday, and Wilson was sworn in to his second term in private) and he focused on international events. Wilson had done his best to morally and mentally prepare the US for going to war, but the nation was far from ready militarily.
During the next Cabinet meeting, Wilson asked if he should speak to Congress before his next scheduled address which was on 16 April 1917. The Cabinet urged action without delay, arguing that the US was already in a state of war with Germany. Even the pacifist in the Cabinet, SecNav Daniels (also a close friend of former SecState William Jennings Bryan), supported war with Germany. On 30 March 1917 Wilson started to prepare his address to Congress, which he had rescheduled for 2 April 1917. House was a huge supporter of the speech when Wilson read it to him in private, since it featured much of what House had suggested to Wilson since the Great War began . . . but as much as House would like to claim at least partial credit for the address, it was a Wilson speech all the way.
Henry Cabot Lodge worked his way to Wilson to personally congratulate the President.
On 4 April 1917, after a quick debate, the Senate voted in favor of a declaration of war by a vote of 82 to 6. The House of Representatives followed suit on 6 April 1917 voting 373 to 50 for a declaration of war. Among the 50 that voted no was the first female representative in US History, Jeannette Rankin (MT), who had been pressured by both hawks and doves and wanted to abstain; former Speaker Joe Cannon told Rankin to vote her conscience. On 7 April 1917, Wilson signed the joint resolution declaring war on Germany, even though the US military at the time was ranked between Belgium and Portugal.