Important events in Europe
Arguably, the most important event in Europe in 1939 was when Nazi Germany invaded Poland. This invasion directly violated a previous deal made by Germany, Great Britain, and France. As a result of this, Great Britain and France declared war on Germany in September of 1939.
Besides that invasion of Poland, the Soviet Union and Germany signed a non-aggression pact in 1939 as well. This was important for the time being, as it prevented Germany from having to fight a two front war.
Important events in the United States
The US passed the Neutrality Act of 1939. The goal in passing this law was to avoid being dragged into a foreign war. This law stopped America from trading arms with countries that were involved in a war.
Okay, so, just from the top of my head, I think that it is because of the growing belief of "Manifest Destiny" in the nineteenth century. I'm not sure if this is the actual right answer for your question, but I do know that Manifest Destiny was in the nineteenth century and was the widely held belief in the USA that American settlers were destined to expand through out the continent. And I think both the USA and Europe wanted to expand, it was kind of a copetition/conflict they had. This was actually how Canada and Alaska came to be I believe. This was a simple explanation btw. cx
Answer:
for violence because if you see French wanted to fight Haitian and basically just to start violence around that country
