I'm pretty sure his biggest objective in the civil war was to (B.) which is Save the Union.
One branch of government can check the other through the usage of "Checks and Balances", which states that no one branch can become to powerful, as the others have the right to suppress the other branch's power.
hope this helps
...he believed in the limited use of federal power but also that states were not truly sovereign.
REA Rural Electrification Administration
Souths economy depended on mostly cotton. when the cotton gen fastened the process, they mass produced it. and made lots of money than before. such was depended on agriculture while north had factories. yet cottons still didn't make that much as industries
