Was the united states justified in entering the first world war? why/why not?

Yes and no, they were justified in that they were the protecting their allies but also it was not at all their fight, they had no purpose in entering aside from ending the war, overall yes they were justified but only to end the war.

frederick william of brandenburg-prussia trained his son, frederick, to be a hardy soldier. but frederick disliked rifle shooting and horseback riding. unlike his father, he was interested in french literature. he enjoyed poetry and music and, like some others of the enlightenment, he scoffed at religion. his father thought him soft, frivolous and unmindful of his duties. and when frederick refused to put his signature on a right to succession, for a few moments his father strangled him.

it increase by 12% a year from 1812-1820