He is a Rockefeller Republican (Republican but more liberal on social issue)

Example: https://www.sandiegouniontribune.com/news/immigration/sd-me-welcoming-san-diego-20190204-story.html

Also he used to be a NeverTrumper

https://www.nbcsandiego.com/news/local/faulconer-no-trump-no-border-wall/2006096/