How did the north achieve victory in the civil war

answer; andrew jackson approved nullification by signing it into law,and john calhoun opposed it saying it was unconstitutional;

the triple alliance. germany and austria-hungary were already allies by 1879 when, worried about a threat from russia, they formed the dual alliance. italy joined the group in 1882. there was a concern about a possible attack from france and the alliance needed powerful friends to defend it.