What Do We Know So Far About President Trump's Tax Returns?

The fight over President Trump's tax returns continues to escalate. On Monday, Treasury Secretary Steven Mnuchin said in a letter he would not release Trump's tax returns to Congress despite requests from House Democrats.

Here & Now's Robin Young speaks with David Cay Johnston (@DavidCayJ), founder and editor of the nonprofit news service DCReport.org, who's reported on Trump's business dealings and finances for three decades.