In this world the US was successful in annexing Canada. In the war of 1812 this event would change the course of american history forever.
The first POD
When the british attempt to invade D.C. They are stopped in their tracks. By the battle of the great lakes the US secures Toronto and Quebec succesfully annexing Canada. The United states took Greenland in 1821 with little opposition.
In 1841 with the annexation of Texas the US went to war with Mexico annexing them in 1842 along with central america. When the US went to war with russia over Alaska in The Russo American war of 1883 (note the civil war occurred the same in the OTL) the US proved itself by taking Alaska. And the Islands in the north pole and Arctic circle.
In 1889 the US went to war with Spain and France over the Caribbean The US was successful in taking the Caribbean the US turned to the pacific islands and evicting Spain and France by 1895. The Us started absorbing Latin america with little opposition.
Turn of The Century
By 1901 the US was the largest nation on Earth by uniting the Americas. 1912 the start of World War 1 or The Great War. When the allies cried for US aid but the USA instead decided to invade Africa. The US had created A much more powerful military than the world having much of OTL WWII tech due to constant war and deals with corporations. The US steam rolled African colonies. The US had taken all of Africa and went to war with the ottomans bringing the Arabian peninsula under US control. In 1921 WW1 ended with an Allied victory.
In 1930 the US left loyal republics in Africa and Arabia. In 1932 The Nazis took power on Germany. The US was the most advanced nation on the planet developing nuclear power and weapons. The US escaped the world depression with OTL 1970's tech in the 1930's.The US however did not share this technology with any nation. The Nazis then became allies with the US in 1940 President FDR met with Adolf Hitler. But when the CIA found out about the Final Solution the US encouraged the Nazis to keep the super smart and strong Jews in the US and just have them live in ghettos not death camps and finally Nazi Germany agreed. With the scientific Germans by their side the US developed technology that we have today in the 1950's. Then Germany invaded Poland, Belgium, And the Netherlands. France tries to fight back but was conquered. The US occupied Britain in 1953. With Nazis full control of all western Europe they assaulted and obliterated The USSR. America and Germany then entered a cold war with Germany having full control of Africa and Europe and the US controlling japan and china. And all south east Asia and Australia.