They wanted more power for state governments.
Answer: Originally, the whole point of the war was to preserve the Union. However, the Emancipation Proclamation made the war about the abolishment of slavery.
Long explanation: Marshall's ruling established the precedent of judicial review by which the Supreme Court has the final say on whether a law is constitutional or unconstitutional.
Short and simple Explanation: John Marshall established judicial review through it. The judicial review that was created allows a better system of checks and balances for the other branches of government to ensure that all actions are constitutional.
The best known statement of the theory of nullification during this period was said by John C. Calhoun
Biological determinism is a canard that has repeatedly been explained away by evolutionary informed scientists since time immemorial. Humans are an inextricable mix of their genes and their environments. As a matter of fact, genes get turned on or off as a function of environmental inputs. Evolutionary-based cognitive computational systems take information from the environment to get activated. Natural selection itself, the foundational mechanism of evolution, is shaped by the selective forces within a specific environment. Hence, there is no such thing as biological determinism.