Well, if you are talking about WW1, the government and businesses of small and large corporations joined together to form a compromise with both paying for the war and making sure that laborers don't go on strike. They let workers have 8hrs a day and higher, safer, no-children work days to make sure they won't protest. This provided Immigrants to take their jobs and keep on producing goods for America. But, this proved not to be good enough over the years so they came up with a plan to let the citizens buy War bonds which then they can regain later but for a higher Value. They also traded with both Great Britain and Germany with weapons (then just traded with Britain, France, and Russia when they joined the war)
Hope this helps :3
