I'm gonna do some more research then i'll get back to you on this.
Internal terrorism and external terrorism both pose a great threat, but terrorism carried out by the United State's own citizens can be much more harmful in the long run. My favorite quote about this is nerdy, but it's from Captain America: Civil War and is stated by the true antagonist of the movie, "An empire toppled by its enemies can rise again. But one which crumbles from within? That's dead... forever." We as a people can rally against an outside threat and rise from whatever they may do to us, but we become exponentially weaker if we must rally against those within our own borders. That's just kinda my opinion.
Two of the major ways in which the Civil War amendments (commonly referred to as the Reconstruction Amendments) added to individual freedoms was that they abolished slavery and involuntary servitude (with the 13th Amendment) and made it so every US citizen had equal protection under the law (with the 14th amendment).
