Knowing what you now know about the major difference between Republicans and Democrats, which one is correct? Or is the answer somewhere in the middle? Who do you agree with and why?

I would simply agree with Democrats, and here is my reasons to support it! Republicans value "Lowering taxes" but they are lowering it for the rich, which is stupid for the Middle class citizen who work there butts off to provide for there family, and taxes constantly going up for them. 2nd reason is, this world, A climate crisis and it only seems like Democratic leaders tend to care about this situation more then republican leaders, It's always a fight between science and politics, especially with Republican leaders. This could just be Extremely bias, and especially because of how this president has acted, and taken away basic rights.  

the doctrine of nullification recommended that states living inside the union have the one-sided, inalienable ideal to void any law made by the national government that could be esteemed illegal.

the united states was shaped based on a general agreement among its individual states. hence, it is inferred that under the hypothesis of invalidation, since the states are the establishment of the union, they have the ability to referee and disprove unlawful laws.