What does the division between red and blue states in the united states refer to

Republicans and Democrats

Explanation:

When we talk about "red" and "blue" states, what we are referring to is the political affiliation of the majority of the population of a state. "Red" states are those where the population predominantly supports the Republican party. These states tend to be more rural, more conservative and more traditional. On the other hand, "blue" states are those in which the population is predominantly supportive of the Democratic Party. This is more common in states with high immigration and large urban areas, such as New York and California.

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