<span>Southern whites feared that freed blacks would seek revenge for past treatment</span>
The crops were all destroyed and long gone. The south had battles on many fields that once grew various types of crops. Men went missing who once tended the fields for the crops to go. Many of them ended up injured or even worse, death. Plantations were left abanded and destroyed. Transportation was gone. Railroad lines had been pulled out or torn apart to prevent the south from moving supplies. Even walking to find a way out was very dangerous for anybody.
When World War I broke out in 1914, all Dominions of the British Empire, including Canada, were called upon by Great Britain to fight on her behalf. So, they kinda had to.
And start.ariot is right. Canada basicly had no choice. It was different in WWII, in which Canadian Parliament debated whether or not to go to war. Canada did, but the fact that she could make a choice was a major step in the growth of Canadian autonomy.
