The chain email said that over 200 years ago, the United States had declared war on Islam, and Thomas Jefferson led the charge! The Barbary powers were Muslim, and religion sometimes crops up in the historical record.
You need to use Form 1040X, along with a new Form 1040, plus any other necessary schedules and forms. Amended tax returns have to be mailed to the IRS on paper for manual processing. The IRS typically processes an amended return about 8 to 12 weeks, but this process can take longer during the IRS's busiest times.
The IRS generally processes e-filed returns within 21 days, but it can take six to eight weeks to process a mailed paper return after the date it is received. You can check on the status of your refund by using the IRS's Where's My Refund? tool.