President Barack Obama is using the N-word to make his case that America is not cured of racism. 

In an interview for a podcast, Obama tells comedian host Marc Maron that the legacy of slavery "casts a long shadow" that is part of America's DNA.

Obama says the measure of whether racism exists is not just whether it's impolite to use the most notorious racial epithet in public.

Obama also decried America's inability to stop a "deranged" 21-year-old from getting a gun and causing great harm - a reference to the white suspect in the racially motivated shooting deaths of nine black church members in South Carolina. 

He says he was never more "disgusted" than when gun control legislation failed to pass two years ago.