Actually, it might be more realistic to suggest that the then-new Republican Party started a civil war in 1861, on the basic premise that a State, once acceeding to union, could never depart (although the Constitution nowhere prohibited State seccession).
The Democratic Party of that era was the 'constitutional party,' and generally promoted a literal or strict interpretation of the compact. The Republican Party of that time leaned towards actions based on feelings of moral outrage, rather than constitutional law. The party names have remained the same, but their philosophies have changed. IIRC, Ronald Reagan observed: "I didn't leave the Democratic Party. The party left me." Today's political parties are not even the same as those our grandparents voted for...