In a Tuesday interview with the AP, Donald Trump stated unequivocally that he would not release his taxes until after the election, citing an audit.
I don't know who the last candidate was to not release their taxes, but it is unprecedented in recent years. (Bernie has similarly stalled, releasing only his 2014 return—complete with some interesting deductions.)
Mitt Romney, another rich man who was reluctant to release his taxes (but, to his credit, eventually did), posted a scathing critique of Trump on his Facebook page that explicitly refers to Trump's decision as “disqualifying.”
The Republican schism makes Hillary vs. Bernie look like Sonny vs. Cher—in the skits, pre-divorce.
One day later, once this decision hit the fan, Trump blasted his critics and said he never meant he wouldn't release his tax returns, only that he would release them after the “routine audit” was completed.
Whenever that is.