Complex sentence: Later, after the Civil War when the 15th Amendment was being debated, Douglass split with the Stanton-led faction of the women's rights movement, because he was in favor of the amendment, which would grant suffrage to black men.
Split into simpler sentences: Later, after the Civil War when the 15th Amendment was being debated, Douglass split with the Stanton-led faction of the women's rights movement. He was in favor of the amendment, which would grant suffrage to black men.