[DiogenesLamp]

The British North American Colonies ‘unilaterally left’ 90 years earlier. King George reacted the same way that Lincoln did.

Not quite. He simply wasn't as willing to get so many people killed as was Lincoln.

[Bull Snipe]

He was also engaged in a major war with France. A far more powerful opponent then the Colonies. He didn’t seem to have an issue getting lots of soldiers and sailors killed by the French.

[BroJoeK]

Pelham: "The British North American Colonies ‘unilaterally left’ 90 years earlier. King George reacted the same way that Lincoln did."

DiogenesLamp: "Not quite. He simply wasn't as willing to get so many people killed as was Lincoln."

No, in fact the British put relatively as much effort into their war effort as the Union put into the Civil War.
The difference was that the British war effort was spread over a much larger battlefield -- from India to the Caribbean, and against several countries allied to Americans, including the French, Spanish and Dutch.

And in 1861 many Confederates realized they needed foreign allies to win independence.
But in 1861 no foreign powers were willing to support a nation dedicated to the proposition that:

"Its foundations are laid, its cornerstone rests upon the great truth, that the negro is not equal to the white man; that slavery—subordination to the superior race—is his natural condition.
This, our new government, is the first, in the history of the world, based upon this great physical, philosophical, and moral truth.[3]"

So, the Civil War was lost by Confederates before it even began.