I turned it in around May 2020. No, slavery certainly was a factor. I'd say it ranked anywhere from 2nd to 5th or 6th, depending on the state. The issues were different for everyone. Here's how I summed it up:

"The issues of slavery, westward expansion, internal improvements, and others were paramount to different interests in different states, and at different times. The shifting interests of each state defined what each political party platformed on, and this is one reason why the tariff and revenue issues do not normally pop up during a traditional study of the Civil War."

Also,

"...for the sake of focus and clarity on the subject, we must first put aside all moral reservations and then concede the fact that slavery was a major issue that led to secession and the ‘War of the Rebellion,’ or Civil War; just as westward expansion, internal improvements, and states’ rights were. Preceding all of these issues, though, were the disagreements over tariff and revenue legislation. Indeed, “freedom from oppressive taxation had caused the American Revolution, the French Revolution, and throughout history revolts and rebellions too numerous to mention. The War of the Rebellion, as it was officially called, had at its core what has been at the core of most rebellions from our earliest historical records.” Revolutionary wars; civil wars; world wars; even the most popular fictional wars, more often than not, reveal the initial motivation for war in the ‘opening credits.’ A long time ago in a colony far, far away…"

It's an interesting topic to say the least.