What does the phrase the buck stops here mean

Well since there aren't any choices i dont know if this is right but nationalism played an important role in the unification of both italy and germany i do believe 

I'm not going to write an entire essay for you but i can summarize the spanish american war for youthe spanish american war starter in 1898 between the u.s. and spain after the u.s.s maine was sunk in havana harbor. we wanted their colonies and we had steel production so we had a steel fleet and literally destroyed the entire spanish armada in the philippines with only one loss. which was a person being crushed on a ship by a box. remember because of the bessemer process we had more steel and steel is stronger than iron. steel guns can shoot 2 miles while iron guns can shoot 1 mile so we just stayed out of range and destroyed them all. we beat the spanish in one year and we got puerto rico, guam, and the philippines as territories and cuba was left as a free country. also we treated everyone worse than the spanish and stole all the territories resources for ourselves.

Cause he knows what’s up