GATE: Thus the United States conquered

Lore Pt.1: The Second Great War

(TLDR: The United States and Japan switch's sides in WWII and the Axis win in 1947)

The world of this United States and ours in identical until September 1st 1939 when The German Reich invades Poland without any consultation with or even warning to its allies, this proves to be the proverbial straw that broke the camel's back for the German Reichs asain ally of convenience Japan who have grown discontent with the alliance due to a lack of communication and trust from their European ally alongside the signing of the molotov-ribbentrop pact which is a non aggression pact between the German Reich and Union of Soviet Socialist Republics (USSR) whom Japan and the German Reich had a pact against in the form of the anti-comintern pact, this had created discontent with the German Alliance which was revoked by Japan on September 4nd 1939 making the de facto allies of The British Empire and they later declared war on the German Reich freeing the British pacific fleet in the pacific and allowing them to move to the atlantic where the navy would be needed most and allowing Japan to expand its imperial ambitions in the pacific and asia without interference.
The United States of America (US/USA) signs the lend lease act which uses the United States's industrial capabilities to produce equipment and send natural resources to the USSR and British with payment only needed later or entirely avoided by returning the equipment to the United States. However it fears the expansion of Japan's empire and deploys a oil embargo to Japan cutting it off from 90% of its oil supply and freezing all Japanese assets in the US.
On December 5th 1941 Germany preemptively invades the USSR in operation barbarossa which is followed by a declaration of war on August 1st making them an ally of the British and the Japanese in the United Nations, meanwhile Japan in hopes of quickly destroying the US the pacific fleet in order to begin peace talks to lift the US oil embargos which has left Japan dry and running out of oil they strike at pearl harbor. The US retaliates by stopping lend lease to Japan's allies and a declaration of war though only at japan. The USSR and the British attempted to avoid conflict with the United States however by March of 1942 due to their alliance with Japan conflict became inevitable and an exchange of declarations of war ensued on March 9th and 11th between the three. The United States officially joins the once Eurasian war and joins the Rome-Berlin Axis, now Rome-Berlin-DC Axis (or just Axis) and makes it a truly World War.
Canada declares its neutrality but is promptly invaded by the US with no hopes to defend to country without aid from the British who now not only cut off from the industrial resources and natural resources of the United States but working against it sends no help as it cannot risk the resources it would take to help Canada as it can no longer replace them and it military machine grows ever weaker every day as it inches closer to starvation.
Fighting goes on in Europe unchanged until mid 1943 when the United States managed to make a pathway through neutral facist Spain, into France,and Finally Germany after a vicious navel battle with the British that put them on the defensive for a short while, with military aid and the natural resources of the United States Germany is able to feed its industrial base without worry of constant bombing raids and resource shortages Germany is able to finally become a fully mechanized military and deply more troops to the Eastern Front to combat the USSR, meanwhile Japan loses at the battle of Midway and loses experiences airman and naval vessels which it cannot replace and is put on the defensive for the rest of the war.
After two years of fighting the United States finishes the development of the atomic bomb in late august of 1945, it will be the sole atomic power of WWII as no other country on Earth as the resources or money to invest in a weapon that may not even work, war rages on for another two years in which over seventeen atomic weapon strikes from the United States on Britain the USSR and Japan have occurred but has only worked to prevent the United Nations(Allies) from winning the war and creating a bloody stale mate
The war ends on February 23rd, 1947 after 98,000,000-127,000,000 lives have been lost, tensions are high and relations between the Axis powers mainly Germany and the United States break down and the two become advisories whilst relations with the USSR don't improve much at all.
Japan and territories in Korea, alongside the remaining portions of Canada become client states of the United States whilst other parts of Canada naimly their western and maritime provinces are annexed the and become States while Quebec gains independence from the remainder of Canada and becomes another client state of the U.S, the U.S keeps all of its territories and annexes Alaska, Hawaii, and Puerto Rico and invades the entirety of Panama and Cuba and annexes them as States as well.
The British are offered a generous peace agreement which even allows them to keep their military as the United States need an ally in Europe to act as first line of defense in case of conflict between the United States and the Rest of the Axis Powers.
The Soviet Union manages to prevent a German invasion and becomes suspicious and paranoid of its neighbors and the Axis Powers, it intervenes in the Sino Civil War on the part of the communist forces who gain control or mainland China running nationalist forces off the mainland and on and Island of the coast of China, communist forces form the People's Democratic Republic of China though is does last long and it along with Mongolia join the USSR, it later forms the Eurasian Comintern Pact as a way to secure military security for itself.
Germany annexes many of its gains in Eastern Europe to create land for Aryan colonization and carves out an empire out of forfeited land from the French and the British in Africa but begrudgingly allows the Italian Empire to take some land in Northern Africa, later in 1951 German and Italys fraile alliance breaks down in the Italia-German war which ends in a German victory and subjugation of the Italian Empire as a pro-German puppet regime is formed , it forms Berlin Accords, an organization to better control its puppet states and protectorates across Europe and Africa.
The United States of America (USA), Union of Soviet Socialist Republics (USSR), and the Greater German Reich (GGR) are left as the sole great powers on earth and soon, the three are locked in opposing directions, with the horrors of technology created in the Second Great War the three are reluctant to fight an out right war. For now they locked in a new kind of war, one of competition and diplomatic action , a Peaceful War.