Except Lincoln didn’t intend to end slavery in the southern states. He thought it was evil, but beyond his powers, at least until the war started. The president is mostly uninvolved in the admendment process.
War powers of the president are greater.
Not only beyond the President's power but also beyond the power of Congress to legislate slavery.
All legislative powers are enumerated in the Constitution and the power to legislate slavery is not among them. Powers not granted Congress are left to the states or the people.
The Constitution did not grant Congress legislative powers regarding slavery, voting, abortion, marriage, flag burning, or to prohibit the citizens from any endeavor in their pursuit of happiness.
The Constitution did provide an amendment process to add, or subtract, powers of legislation. The 13th amendment took the power to determine if a state would be free or slave away from the state and added it to congress’s legislative powers. The amendment itself is not legislation but it provides Congress with the power to enact legislation regarding the amendment. Section 2 of the 13th amendment adds the legislative power … Section. 2. Congress shall have power to enforce this article by appropriate legislation.