If you work for the post office, you're a civil servant. The Civil Rights movement focused on the notion that all American citizens were entitled to the same basic civil liberties.
There is also time limit to consider for sending the amended returns, and it is generally three years from the time you filed the returns or two years after the tax payment (whichever is later). If you plan to amend more than one tax return, you have to file separate 1040X for every one you want to change.
Under Federal law, there is a time restriction on how long the IRS has to collect unpaid taxes. This time restriction is most commonly known as the statute of limitations. For most cases, the IRS has 3 years from the date the return was filed to audit a tax return and determine if additional tax is due. After the IRS determines that additional taxes are due, the IRS has 10 years to collect unpaid taxes. Most taxpayers can rest assured that after 3 years, it is highly unlikely that the IRS will attempt to audit them and assess additional taxes against them. However, there are certain exceptions to these rules.