Conversation so far:
when did the states seceded during the civil war
Secession, as it applies to the outbreak of the American Civil War, comprises the series of events that began on December 20, 1860, and extended through June 8 of 1861.
what is the term for advocates of secession
Advocates for secession are called disunionists by their contemporaries in various historical documents.

Question: how about the opposite
Self-contained rewrite: what is the term for the enemies of secession