Why the USA and Australia are so alike

Even though I'm an Aussie with red dirt running through my veins, I can't help drawing a parallel between our two nations. Both the offspring of a empire that dominated the world.
Both fiercely independent and proud of our unique lands and peoples. We have stood side by side in all of the wars of the 20th century. And continue our alliance to this day. Semper Fi!
And we both enjoy getting one up on the 'Poms'