sentences:  Washington presided over the Constitutional Convention in 1787, during which it became obvious how explosive the slavery issue was, and how willing the antislavery faction was to accept the preservation of this oppressive institution to ensure national unity and the establishment of a strong federal government.The Constitution allowed but did not require the preservation of slavery, and it deliberately avoided use of the word "slave" which could have been interpreted as authorizing the treatment of human beings as property throughout the country.Each state was allowed to keep it, change it, or eliminate it as they wished, though Congress could make various policies that would affect this decision in each state.