"Our Peculiar Institution" was the euphemism for slavery used particularly in the antebellum South. I haven't been able to find when the term first originated but it was an extremely popular euphemistic term that newspapers and public speakers, i.e. preachers and politicians, used in order to keep from having to utter the word slavery. I first came across the term, Our Peculiar Institution, while reading John Jakes' Civil War trilogy, North and South, which ought to be, by the way, required reading in every high school in America.
Nowadays we find it peculiar that when Thomas Jefferson first wrote the words, "All men are created equal," he was certainly not referring to his own male slaves or those of George Washington and the many other Founding Fathers who were slave owners. Jefferson, we can only imagine, must have had second thoughts about those words. Of all the Founding Fathers he was one of the most intellectual and forward-thinking and he must have known that those words would come back to haunt the nation that he was having a hand in creating.
Most of us now even find it somewhat peculiar that it took so long for the U.S. Supreme Court to outlaw segregation (Brown v. the Board of Education, 1954). It now, with hindsight, seems peculiar that it took our country so long to ban State anti-miscegenation laws outlawing interracial marriage (Loving v. Virginia, 1967).
The enslavement of African Americans in what is now the U.S. formally began in the 1630's and lasted for some 230 years. The Civil War ended the enslavement of African Americans only 143 years ago and until only 41 years ago it was perfectly acceptable for States to have laws making it illegal for a white citizen of our country to marry a black citizen.
Most of us find it peculiar now that our ancestors used the Bible to justify Our Peculiar Institution. "[Slavery] was established by decree of Almighty God...it is sanctioned in the Bible, in both Testaments, from Genesis to Revelation..." Jefferson Davis, President of the Confederate States of America. This statement is correct. I defy you to find one sentence in the New or Old Testaments that denigrates the practice of human slavery.
A lot of us find it peculiar that the Reverend Jeremiah Wright is angry that attitudes are less easily changed than laws. Our Peculiar Institution was legally deconstructed by the Emancipation Proclamation a hundred and forty something years ago. His point is that the Emancipation Proclamation and Brown v. the Board of Education and Loving v. Virginia not to mention the Civil Rights Act of 1964 took far too long in coming and did little more than put words on paper and certainly didn't etch those sentiments onto the hearts and minds of a great many of us Americans who have yet to totally disown Our Peculiar Institution.