One consensus you will likely find is that near the bottom of most polls is our 14th president Franklin Pierce. Franklin is credited with having almost as much to do to cause the civil war as anyone else in history. He was a drunk, warmonger, racist, anti immigrant tyrant. His domestic policy included keeping Irish, Italian and Catholics from immigrating, while attempting to ship those already here back. Jeff Davis served as his Secretary of War. His own party didn't nominate him for reelection.
Well, Franklin survived his one term presidency, and had a grandson. His grandson had a granddaughter who is still very much alive. She was born Barbara Pierce. Barbara's distinction is to be one of only two women whose husbands and sons were US presidents.
Perhaps you recognize Barbara (nee)Pierce better as Barbara Bush.
Is it nature or nurture? Perhaps even mediocrity is hereditary? The jury is still out.