"What's Going On?" originated with Ronaldo "Obie" Benson, a member of the Motown group the Four Tops, who penned an early version after witnessing police violence against anti-Vietnam War protesters in Berkeley, California. Benson took the song to Gaye, whose brother had recently returned from the war and whose cousin had died in it, and Gaye made it his own. The song's lyrics both implicitly references the violent rifts in American society ("Mother, mother/ there's too many of you crying") and explicitly questions the war ("We don't need to escalate ... war is not the answer/ for only love can conquer hate"). These lyrics made it ripe for controversy, enough that Gordy discouraged Gaye from recording the song, saying "Don't be ridiculous. That's taking things too far."
Ultimately, Gaye went on a recording strike to force Gordy to release "What's Going On?" Not many artists had the gumption or the clout to stand up to Gordy, and as such the single's release foreshadowed his future disagreements with Gordy and eventual split with Motown. The single reached number 2 on the Billboard Hot 100 chart and would go on to be named the fourth-greatest song of all time by Rolling Stone. The album What's Going On, released the following May, was a concept album that further explored Gaye's opposition to the war as well as other sensitive topics like poverty and drug use. The song "Mercy Mercy Me (The Ecology)" is one of the earliest examples of environmentalist messaging in mainstream pop music. Critics continue to rate the album and its title track among the most influential recordings in modern musical history.