Controversy over which DMARC setting will best protect the 2020 presidential campaigns

This story quotes Seth Blank, Valimail’s Director of Industry Initiatives and secretary of the IETF group overseeing the DMARC standard: “The email industry is in agreement that both 'quarantine' and 'reject' settings are considered real protection. With either quarantine or reject, no suspicious messages make it to a user’s inbox, period. People look at their spam folder very rarely, and when they do, they tend to be suspicious of what’s in there. But to say that quarantine is 'not secure' is not correct.”