"You will hear a couple small but loud voices today speak obsessively not of our national greatness, but of our national imperfections," Mr Vance said from the USS Kearsarge.
"They'll talk about America's sins with the anger and zeal of a brimstone preacher, but without any of the grace or forgiveness that must be present in the Christian faith," Mr Vance said, adding that these critics "misunderstand the essence of America".