OK –Literally. Martin Van Buren, the eighth President of the United States, was born on December 5, 1782 in Kinderhook, New York, making him the first American president born a U.S. citizen. Van Buren was also known as “Old Kinderhook, or “OK,” the origin of that American expression.
The last, perhaps the greatest, of the prominent sources of discord and disaster supposed to lurk in our political condition was the institution of domestic slavery. ..”I must go into the Presidential chair the inflexible and uncompromising opponent of every attempt on the part of Congress to abolish slavery in the District of Columbia against the wishes of the slaveholding States, and also with a determination equally decided to resist the slightest interference with it in the States where it exists.”
Martin van Buren: “Inaugural Address,” March 4, 1837. Online by Gerhard Peters and John T. Woolley, The American Presidency Project. http://www.presidency.ucsb.edu/ws/?pid=25812.
Read more about Martin Van Buren in this post.