O Cascadia

The main POD's in O Cascadia are

Due to the Balkinized nature of the US after 1860, with nations rising and falling, the Americas become occupied, and thus not able to intervane in the Great War, so the war ends in a devastating stalemate between both powers. With Europe devastated, Hitler, and many other OTL WWI veterans dead, and the Americas Balkinized, Japan expands, conquering the Pacific. It is only after Japan takes the San Francisco Bay, in the Battle of The Golden Gate, the American states realize that they are under threat. In a joint alliance by Cascadia, California, and several other Pacific/Mountain nations retake California under the leadership of General Theodore Roosevelt. After the Pacific War, California allows Cascadia to annex their northern area, and Roosevelt becomes President of Cascadia, establishing it as the major power in America...
 * The USA and British Canada could not reach a consensus about the Oregon Country, and eventually it became an independent country.
 * The USA won a Pyrrhic victory in the Mexican-American War, and in result, the Southwest became a contested zone between the USA and Mexico, the subject of many skirmishes.
 * Polk was not as good of a President as he was in OTL, and even though he got Texas, New Mexico, and California, he failed to hold on to them very well, due to the high amount of casualties in the Mexican American War.
 * Stephen Douglas is elected President in the 1860 elections, and prevents the Civil War from happening. The 1860 Compromise is made, allowing all states to have slavery, while allowing all non-slavery states the right to peacefully secede.