The statement that U.S. debt not secured by real estate exceeds $3 trillion is false. The U.S. debt primarily consists of Treasury securities, which are obligations of the federal government and are not backed by real estate. Instead, they are backed by the government's ability to tax and generate revenue. While the total U.S. debt is substantial, it is important to understand that it is not solely dependent on real estate as collateral. Treasury securities are considered safe investments, and the U.S. government has a strong credit rating, making these securities attractive to investors.