[lotsofpulp]

The government automatically doing it doesn't preclude from letting taxpayers be able to amend it. The vast majority of people have simple tax returns, and all that information is already electronically flying around with unique identifiers (social security number).

It's trivial for government to be able to automatically produce a tax return that's basically almost all done for everyone.

[lifthrasiir]

This is exactly how South Korea does the taxation. Employeers are required to report employees' incomes and also deduct the tentative tax. The final tax is set by the year-end settlement where you can put documents for income deduction and tax credit to the National Tax Service. Common documents (e.g. credit card expenses count towards income deduction) are electronically available in one place and it is not very hard to get hold of other documents if you are an employee. In the end you pay or get the delta between the tentative tax and the settled tax.