Answer: the British Invasion
Step-by-step explanation:
For a time, the Bakersfield sound was the only homegrown music that could compete in sales against an influx of British bands; this was called the British Invasion, and it sparked a new wave of music and social activism. Psychedelic rock arose from this subculture, which opposed the Vietnam War and supported civil rights and other generally leftist causes. While the energy in this scene remained strong for some time, it soon splintered into competing heavy metal, early art-punk rock and progressive rock.