Like almost every president who preceded him, Lincoln's actions at the time were somewhat controversial. Some of his most controversial decisions might actually be considered now to be abuses of the Presidential power.
When you find that you need to amend a tax return, you need to make sure the statute of limitations on filing one hasn't run out. The statute of limitations, or time allowed for the action, on getting a refund from an amended tax return is three years.
If you were audited by the IRS, you have two years from the date of the federal audit. If you file an amended return with the IRS and the changes affect your Oregon taxable income, you must amend your Oregon return within 90 days of amending your federal return.