Assassination.

The phrase "Union before the war" most commonly refers to the United States' federal union of states prior to the American Civil War (1861-1865). The other "Union" the user might be referring to is the Union of the Crowns of Scotland and England in 1603, which created a personal union, not a full political one, but wasn't a full Act of Union until 1707. The term "assassination swad" is not a known historical term; however, swords used in assassinations were built before the war.