The Supreme Court ruled that a taxpayer who files a fraudulent tax return cannot avoid penalties by correcting it later. This decision in Badaracco v. Commissioner means the government can assess taxes and penalties without time limits, even if the taxpayer tries to fix the mistake. The Court's decision was criticized for being poorly reasoned and a misapplication of the law. This case shows how even top judges can make mistakes in interpreting laws, highlighting the need for careful review of tax cases.