<span>Catholic Church is the answer to your question </span>
They wanted to avoid conflict, they didn't want to get themselves in another war. They also wanted Germany to act as a buffer between Europe and the Soviet Union.
Democracy (?)
You mean, people vote right?
The US before this point had an interest to stay neutral. However, in 1917, Jan 16, the US was informed by the British Empire US to join the war since Germany would help Mexico regain land lost, the US saw that as a problem. This incited them to declare war (This event was known as the Zimmerman Telegram)
So in summary, yes, it was in the national interest of the United States to declare war in 1917
What Was the US Involvement in WW1? ... The reason for America to become involved in WW1 was Germany's unrestricted submarine warfare, which had already sunk several American merchant ships. The U.S. was initially contributed to the war by supplying raw material, supplies and money.
