What was the important effect of the us-mexico war?

The Mexican-American War and the massive territory gained reopened debates over slavery which diminished party alliances and increased sectional alliances. These debates over slavery eventually led to the demise of the Second Party System and paved the way for the rise of Republicanism.

in the 1800s, chinese workers migrated to the united states, first to work in the gold mines, but also to take agricultural jobs, and factory work, especially in the garment industry. chinese immigrants were particularly instrumental in building railroads in the american west, and as chinese laborers grew successful in the united states, a number of them became entrepreneurs in their own right. as the numbers of chinese laborers increased, so did the strength of anti-chinese sentiment among other workers in the american economy. this finally resulted in legislation that aimed to limit future immigration of chinese workers to the united states, and threatened to sour diplomatic relations between the united states and china.