I've been listening to Mike Duncan's Revolutions podcast, and one of the things that comes up over-and-over again is the idea that France was beset on all side by foreign and domestic conspiracies that plotted the demise of the nation. Many high-level members of the revolution were killed for suspicion of being involved in a plot against the nation on very flimsy evidence.
Is there a way to understand this social phenomenon? I'm having a hard time believing that anyone involved in the revolution honestly believed in massive conspiratorial plots, or that any of their fellow revolutionaries might be involved in a conspiracy.
The Brunswick Manifesto published by the counter-revolutionary Austrian and Prussian armies on 25 July 1792 pledged to raze Paris if the royal family was harmed. This obviously stoked huge fears that there were conspirators within the capital, starting with the King and his court. Tim Blanning in The French Revolutionary Wars: 1787-1802 asserts this was key in driving the paranoia that drove the increasing severity of the terror.
The primacy of this foreign policy focus has been criticised for vindicating the cruelty of those who perpetrated the terror, and there were obviously plenty of individuals in Paris in 1782/3 who were willing to take advantage of chaos for personal advancement.
Nevertheless, i reckon the fear was real. France had taken historically unprecedented steps towards reshaping the state and it was only tenuously under control at the best of times. All this was massively threatened. The Allied armies were not more than 100 miles from Paris, Fleurus hadn't yet happened and it was pretty unclear whether there was anything the revolutionary government could do to stop them. And all across the peripheral regions of France there were counter-revolutionary reactions and uprisings that filtered back to Paris and then bounced around the revolutionary echo chamber. It'd have been pretty hard to tell friend from foe.
France actually was threatened on all sides by reactionary powers eager to strangle Republicanism in its cradle. This might not qualify as a conspiracy, since their marching armies into France with the express intent of restoring the Bourbons wasn't exactly subtle, but it was a clear threat to the Revolution's survival.
As for internal conspiracies, there were a few. The Vendémiaire uprising, famously crushed by Napoleon and his 'whiff of grapeshot', was a royalist assault on the republic in the heart of Paris itself. This is a little later than the Reign of Terror, but a few French Royalists tried (and came very close to) blowing up First Consul Bonaparte as the first step of a plan to restore the monarchy. The very popular General Moreau betrayed the French Republic and offered his services to Great Britain and Royalist agents.
Of course, many (if not most) of the royalist plots that got people sent to the guillotine were entirely imaginary, but there were more than enough very real threats to make the state of paranoia which gripped France during this time period very easy to understand.