Which act did sam houston predict would "convulse the country from maine to the rio grande"?

I can take a solid guess and say the induction of new territories acquired during the Mexican-American War. This disrupted the Compromise of 1820 which kept slavery beneath the 36 degree parallel. Most of the new territory acquired was beneath this line upsetting the balance between free and slave states in congress which ultimately led to Bleeding Kansas, Popular Sovereignty, The compromise of 1850, and The American Civil War. Hope this helps.

Amunicipal department