What was the most important principle of the republic to George Washington? A. The abolition of slavery
B. The new political parties
C. The Supreme Court
D. The union of the states

D.

Explanation:

The union of state is the answer

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answer; andrew jackson approved nullification by signing it into law,and john calhoun opposed it saying it was unconstitutional;

very positive impact on our industries in the west, sine they promoted settlement and increased the ways in which goods could be transported to market.