The united states' status of first place among industrial nations was a result, in part, of:
an industrial slowdown in europe
the advent of mass production
the growth of the agricultural industry
the war of 1812

The United States' status of first place among industrial nations was a result, in part, of "the advent of mass production," since the United States was the leader of the Industrial Revolution (after Britain that is, but the US eventually had more man power and better access to resources). 

Americans agreed to the settlement terms established by the mexican government.