In 1998, Congress passed a law that required the IRS to start pre-filling tax returns for “appropriate” taxpayers within a decade. But the IRS never did. 

The Treasury Department published a report in 2003 on what it would take to follow that law. It noted that the United States has more complicated deductions and credits than most countries, and that Americans wouldn’t want pre-filled returns if it meant getting their refunds later in the year.