1) Checks and Balances- This idea is implemented in the Constitution to ensure that no one branch of the federal government gains too much power. For example, the legislative branch(Congress) can approve a bill that will then be sent to the executive branch (President). If the president does not like the bill or thinks that it violates the rights of citizens, he/she can veto the bill. Vetoing the bill stops the bill from becoming a law. This check on power ensures that Congress makes laws that do not violate the rights of citizens.
2) Anti-Federalists do not want to ratify the Constitution unless it includes a Bill of Rights. The Anti-Federalists are worried that the Constitution gives too much power to the federal government. Having a strong central government caused problems when the US was still part of Great Britain. This is why the Anti-federalists are fearful of this type of system.
3) Federalists want a new constitution passed because it will fix America's weak political structure. Before the US Constitution is implemented, the constitution being used is known as the Articles of Confederation. This constitution has an extremely weak central government, allowing for disunity among the states.
The Union originally wanted to reunite the country, but after the Emancipation Proclamation of 1863, the Union goal changed to include the abolition of slavery. The Confederacy had the same goal throughout the war: to incorporate all slave states and secede from the Union, survive, and defend its territory.
