Final answer:
The situation that the amendment mentioned would worsen according to the writer is the Civil War. The Thirteenth Amendment, supported by Abraham Lincoln, was necessary to end slavery permanently, but it was believed to potentially intensify the conflict.
Step-by-step explanation:
The student's question refers to an amendment that, according to the writer, would worsen the effect of the existing sectional hostility and potentially make the conflict more intense. From the provided information, it is clear that the situation in question is related to the Civil War. The amendment being discussed is the Thirteenth Amendment, which abolished slavery in the United States, following the Emancipation Proclamation that had initially freed those enslaved in rebellious states. Abraham Lincoln supported the move toward such an amendment as he saw it as necessary to give emancipation the force of law. The eventual passage of the Thirteenth Amendment led to the permanent end of slavery, fulfilling Lincoln's vision and promise.