Many have speculated what Donald Trump's tax returns may reveal -- and now the New York D.A. is likely to find out. The Supreme Court ruled Trump has no “immunity” to hide the returns. Award winning investigative journalist David Cay Johnson, who obtained some of Trump’s records, explains what the returns may hold – and offers clues from the new Supreme Court decisions about a separate Congressional case that could ultimately make the returns public, in this interview with MSNBC's Ari Melber.