IF the Union allowed the CSA to form w/o a war.....

Secession was not unconstitutional until four years after the war.

That decision was finally made to justify the illegal war that proceeded the ruling. Lincoln actually had no constitutional right to conduct such a war.

 

The USA & CSA woulda both been vulnerable to foreign intervention, especially by Britain, France, & even Mexico.

Several British observers watched some of the battles and/or observed armies of both sides preparing for battle. While acting innocently, their real mission was to see how vulnerable each side was to a British invasion. They drew two conclusions from their observations:
1. A British invasion would likely cause both sides to set aside their quarrel for awhile to deal with the British.

2. While the British Navy was still supreme, it could not land enough troops to have a chance against the Americans. They had enough to worry about with France & the Austro-Hungarian Empire, & its allies Germany & Prussia. Queen Vicky & most of her PMs knew the USA was rapidly becoming a world powerhouse, & they'd best have her as an ally, not an enemy.

When the importance of cotton would fall off, the South would be in trouble, once her old money would begin to run out. And I believe peoples' attitude toward slavery would have changed. I believe the seceded states would eventually be forced to seek re-admission to the Union, some earlier than others, but those recalcitrant states would've come around upon finding themselves isolated.

 

Agree sir

 

Mexico might've tried to take back Texas, California, etc. but not while there was a strong Confederate army ptrsent. Besides, Mexico was very unstable while the Civil War was ongoing here, & when Maximilian was appointed emperor, he had no desire to engage his northern neighbor an any hostilities. Neither did Benito Juarez, who overthrew Max & became President.

 

Roby, you are partially correct, except....
You are missing that while slavery was predominant in the South, the North also had slaves even during the Second Revolutionary War (you call it the "Civil War"). If you wish to argue that they didn't, then please explain the Corwin Amendment. In the North, which passed the Amendment, slaves were slaves for life. Whereas in the South slaves usually had the opportunity to earn their freedom. Please don't get me wrong, I'm not in support of slavery no matter how you dress it. But the facts remain the same. And when you start talking about the French and the Spanish, you really aren't covering the story well. Both had slaves, except instead of being black and from Africa, they were Native Americans. Both the Spanish and the French were notorious for their cruelty, which was actually outlawed in the then-US (North & South both).