Donald Trump's foreign and domestic investments are an unprecedented conflict of interest and clearly will influence his policies. He should release his taxes for the sake of transparency like all modern presidents. Trump needs to be pressed on his claim that he's under tax audit and that he'll release them when it's done. Whether his assertions are even true or not he needs to be held accountable. It seems clear increasing public pressure from all sides is warranted.
We realize the IRS wouldn't comply if he actually is under audit, but that's secondary. The primary objective is to get so many signatures that the White House will have to respond to the petition, and Trump will have to continue to answer questions about his foreign and domestic investments and conflicts of interest.