re: #175 Nojay UK
Actually, about 150 years or so. There’s a weird bit of US history that’s not taught in schools much, cross-border raids by armed Fenian gangs based in New York state into Canada in the 1870s. Britain basically said “Nice White House (built by slaves) you got there, shame if it was to catch fire again”, the US government stepped in and the raids stopped.
Also, the northernmost battle of the Civil War, Confederate sympathizers from Canada raided the town of St. Albans, Vermont.