In 1914, we start mobilizing for war. Only the President and a few advisors know we are actually getting ready to invade Canada. Then in 1915, we attack Canada. Could we have conquered it? In 1915, Canada had a population of 8 million people. We had a population of 100 million. What did we get out of World War I?
Well admittedly we could not have done a lot at the time but Germany was starving and collapse would have happened anyway.
Then it would not have been just England but the might of the British Empire. Forces and weaponry from Great Britain, Australia, New Zealand, India, and over 50 other countries all sailing for both US coasts.
Think The Brits wouldn't have bothered?
Argentina thought that. Britain in recession and industrial strife,....... na they wont send a fleet halfway down the globe for their silly Falklands.
Wrong and it took a few months to route and send them packing.
Britain is a history of thousands of years fighting wars!
If you could not beat a bunch of paddy farmers in Vietnam at your peak, how would you cope with the greatest empire in history, at our peak?