In the months leading up to world war i, the united states wanted to maintain its neutrality because

United States expressed its neutrality during World War I because it was indulging in heavy and active trade with European countries.

Explanation:

United States initially expressed its open mindedness and remained impartial but German Submarine vessels entered the US ports and caused a great damage to the business and trade that was carried on actively in American ports.  

This prompted to prepare for an assaulting attack by United States on Germany. US, which remained nonaligned initially, joined hands with the British and France and other allied powers to fight against Germany.

immigrants from northern and western europe continued coming as they had for three centuries, but in decreasing numbers