The doctrine of nullification was practice to halt correctional power over states rights who exercised this doctrine

This doctrine was exercised by Southern states only.

It stated that states kept the authority to define in which circumstances federal government exceeded its powers, declaring acts to be void and of no force in their jurisdiction, previously considered unconstitutional. Initially stated by Thomas Jefferson and James Madison in the Virginia and Kentucky Resolutions of 1798–99, it was supported on the assertion that the Union was a compact of sovereign states, for instance, had the natural right to make such decisions.

i beleive its 1)aids

the right answer for the question that is being asked and shown above is that: "their policy of "divide and rule" pitted political groups against each other to keep any one group from becoming too powerful.  " the  participant in european imperialism is being described below is that  their policy of "divide and rule" pitted political groups against each other to keep any one group from becoming too powerful.