The better question would be: if there was no slavery in the U.S. would there be a Democrat Party in the U.S.?
The highest priority of the Democrat Party was to promote and expand the slave system.
The Civil War was not caused by slavery, it was caused by secession.
Americans, including Lincoln, did not want a war over slavery.
Democrats wanted to create a slave based economy in the Midwest and the West. This led to the creation of the Republican Party in Wisconsin in 1854.
The plan for secession was in place since about 1850.
“The plan for secession was in place since about 1850.”
At least as far back as 1776.
It was caused by the secession of states that produced a great sum of money which flowed through the pockets of powerful Washington DC and New York interests.
When Cuba wanted independence, there were few to none opposed, because it was not making the Northern elite a great deal of money. Same with the Philippines, and Puerto Rico, of course, has an open invitation to leave at any time they so desire.
Again, none of them have major amounts of production which would cause great losses to the power blocks currently in control of our government.
But the South did. The South produced 73% of all the taxes flowing into Washington DC in 1860. It produced the vast bulk of American trade with Europe in 1860, with virtually all of that money flowing through the pockets of New York shippers, bankers, insurance agents, distributors and so forth.
The South was a huge economic cash cow for the Northern powerful.
So to be clear, it wasn't secession that cause the war. It was the secession of states producing great sums of money for the powerful interests in the North, that caused the war.
In other words, it was about who was going to control that monetary output of the southern States.
Beyond that, the Declaration of Independence asserts the right of all states to leave whenever they come to believe a government no longer serves their interests, and so therefore the Southern states had a moral and legal right to leave the Union when they came to believe it no longer served their interests.
Still doesn't answer my core question re if there had been no institution of slavery, would there have been a Civil War. To take it even a step further, would America have been able to decouple from England and have the wealth and will to win a revolution. A broader guess by me is that we would still be in the orbit of England like Canada and Australia. Even may have fractured into more than 1 country. Moot but interesting to surmise.