Call might location play a part in whether New Mexico and California became slave of free states?

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according to me surely location had played a major part, why new Mexico and California became slave of free states, as the geographic positioning of these parts gave quick access for invasion and gaining the ultimate authority for the invaders

from the conditions of the working class in england by friedrich engels,the main idea is :

answer; ///(1) blank; henry clay; (2) blank; secretary of state; (c)is your answer; ///good luck