Former Virginia AG Ken Cuccinelli made a good point this afternoon on Fox News, saying that Northam has nothing to lose by refusing to resign. He can't be impeached for 3o-year-old yearbook photos and after his term expires, he'll never be elected to another office in Virginia, so he might want to drag this out as long as he can.
It should be noted that there's a huge difference between wearing blackface to denigrate people of color and dressing up as Michael Jackson for a dance contest. The left's "cultural appropriation" blather notwithstanding, most rational human beings understand the distinction.
It appears the press conference didn't have the desired effect:
He should have tried crying. That usually works for Dems (but not Republicans, of course).