Stevie Wonder's new song, "Can We Fix Our Nation's Broken Heart"

Ruben Bolling

Screengrab: Republic Records / YouTube.com

Stevie Wonder, who hasn't released a new album in almost 19 years, just released his first new single in four years, "Can We Fix Our Nation's Broken Heart."

"The track is a tender plea for unity built around dextrous acoustic guitars and a melange of light percussion, while Wonder also laces it with piano, bass, …