The correct answer is number 3: In the debate over the Thirteenth Amendment, Democrats in Congress pushed for the reinstatement of states’ rights.
In 1864, an amendment abolishing slavery passed the U.S. Senate, in the debate all the Republicans were in favor, but the Democrats voted against, instead, they pushed for the reinstatement of federalism and states’ rights. Some of their arguments were that to free slaves would result in a "revolution", threatening the nation's peace, and the measure would also lead to give the slaves full citizenship in the future.
When the Congress convened to take the final vote, in March 1865, the majority of the Democrats still disagreed to amend the Constitution. However, the amendment passed with 119 in favor and 56 against. Only sixteen Democrats approved the measure and some others Democrats didn't even vote.