The 1960s were a tumultuous, but crucial period in the development of professional soccer in the United States and Canada - with teams from Scotland, of all places, playing a particularly interesting role.

The dividing line for the modern North American pro game, of course, was the breakthrough, near-live (two-hour-delayed) NBC-TV network telecast of the 1966 World Cup final between eventual champion England and West Germany - the first-ever national standalone broadcast of the sport.

Prior to that watershed, it was sports entrepreneur Bill Cox's International Soccer League that imported full major European & South American teams to play in a senior-level competition in largely East Coast urban centers and first-generation immigrant communities. Among the ISL's regulars were three Scottish sides - including Kilmarnock FC, which played four seasons and made the 1960 final.

Immediately after the World Cup, no fewer than three groups of eager sports owners sought to launch a full-fledged domestic North American league; by 1967, two competing circuits bowed - including a hastily-assembled United Soccer Association, featuring full-team ISL-like imports - but under noms de plume of North American cities. Front and center were Scottish stalwarts Aberdeen FC - masquerading as the District of Columbia's "Washington Whips."

UK football writer Mark Poole ("99 Iconic Moments in Scottish Football: From the Famous to the Obscure, Scotland’s Glorious, Unusual and Cult Games, Players and Events") tells us the stories behind these two curious Scottish contributions to US pro soccer history.