It’s unclear what year or years the document is addressing.
“The party of ‘norms’ and ‘decency’ strikes again. We will never back down,” Hegseth added in his tweet.
He is not the first cabinet appointee to receive a letter from the IRS.
In 2009, it was famously revealed that President Obama’s Treasury Secretary appointee, Timothy Geithner, owed the IRS about $35,000 in unpaid Social Security and Medicaid taxes.