Your challenge today is to have an alternate version of the cold war. However, instead of Capitalism vs Communism most of the ideological will be based on Republicanism vs Monarchism. POD can be anywhere from 1700-1850.
How exactly would everything happen as IOTL with a POD during or before the American Revolution? Butterflies, my friend.The British are more lenient with the Americans and so America stays in the empire eventually becoming a dominion. WW1 happens as in OTL but Kerensky takes Russia out of the war and has the romanoffs shot. Bolsheviks never take over. In WW2 the russians kick out the royal families of the eastern european nations and declare them republics. After the war get the russian propaganda to go on about how the west is governed by kings and the east is truly democratic and then get the west to respond.