Interesting to know the backstory on this one, but you would think a law professor at Harvard would at least read the law, before going to court.
The professor failed to file tax returns with the IRS for many years, and then he went to Tax Court to dispute the taxes with the IRS. In Sullivan v. Commissioner, the United States Tax Court held for the IRS. The professor failed to respond to many notices, and with the IRS, procedure is extremely important. That was one of the reasons he lost big. IRS records showed that Sullivan failed to file tax returns from 2005 to 2013. Eventually, the IRS caught up with him and was trying to collect an outstanding tax balance from 2012 and 2013. The amount due for just those two years was $1,231,775.
Over the course of 2017, the IRS sent Sullivan three letters informing him he would need to file his 2012, 2013, 2014, and 2015 returns in order to contest the amount he was required to pay. At one point, the assigned IRS settlement officer scheduled a date for a telephone hearing; Sullivan did not call in, nor did he provide financial documents, or tax returns. The IRS tried to prompt Sullivan at least seven times about his outstanding balance.