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Which plan proposed to maintain open trade between china and western nations? open door policy national sovereignty missionary diplomacy salutary neglect

How does the supremacy clause of the u. s. constitution affect the states? o a. it requires each state to establish a supreme court. b. it declares that the federal government can take away state powers if necessary. o c. it allows state governments to overthrow the federal government if necessary. o d. it ensures that the u. s. constitution overrules each state constitution

What is the main idea of this excerpt