Who were the Copperheads during the Civil War?

The Copperheads were indeed a faction of Northern Democrats who opposed the Civil War's main objectives, including the abolition of slavery. They were critical of President Abraham Lincoln’s administration and often advocated for peace with the Confederacy. Their opposition stemmed from a belief that the war was unnecessarily costly and that a negotiated settlement with the Southern states was preferable.

This group was particularly prominent in the Midwest and expressed their views through various means, including speeches and publications. They garnered support from many who felt that the Union's strategy was overly aggressive and detrimental to personal liberties and state rights. The term "Copperhead" itself was used derogatorily by their opponents, likening them to the venomous snake that could strike unexpectedly, reflecting the perceived threat they posed to the war effort.

The other options do not accurately describe the Copperheads. For instance, Northern Democrats who supported segregation or a pro-Union Republican faction do not capture the essence of Copperhead ideology. Similarly, military leaders opposing the Union's strategy misses the political aspect that defined the Copperheads' opposition during this tumultuous period.