Even with the passage of the Clay bill, the "free soil" movement continues to grow as the growth of slavery into new territories was resisted by "free soilers" in the north who resisted the extension of the reach of the institution of slavery. If slavery expanded, so did the political power of the South, thereby upsetting the delicate balance of power between North and South in the U.S. government. Manifest Destiny which had before become a rallying cry for the nation now divided it along sectional lines as the South became the advocates of expanding Western lands in the hopes of extending slavery while northerners hesitated over the free soil issue at expansion into former Mexican territory. It may not have kept people from going west to mine gold in California, but it certainly raised doubts about the type of society that would grow out...

Racial controversies were complicated even more in California with the influx of Chinese and the crushing of native Mexicans in the new acquired territories (ibid, 415-416).
The expansion of the United States challenged not only U.S. domestic politics, but also its international relations. As noted above, it lead to war with Mexico. The fight over Oregon caused controversy between Britiain and the U.S. As northerners fretted over southern expansion, but not over their own (ibid, 401-402). Again, the Clay bill papered over these differences, but this was only a band aide on a huge wound.

Works Cited

Maier, P., Smith, M.R., Keyssar, A., & Kevles, D.J. (2005). Inventing america: The history of the United States vol. 1. (2 ed.). Boston, MA W.W. Norton.