The first Civil War gives clue how this might play out—a series of provocations (intentional or unintentional) would inflame both sides—think Bleeding Kansas, the Dred Scott decision, the John Brown raid, etc.
John Adams and John Calhoun had a civil discussion about the possibility of civil war as early as the 1820s, but it took until the 1850s to make it happen.
I don’t think any comparable “incident” has happened yet—so we are probably looking at another ten years of peace.
Then—watch out!
If something happens to President Trump.....look out!