I retired in 2017. During 2017 I made a mistake on how I should have taken my IRA distributions and ended up taking a lump sum in January 2018. Then during the rest of 2018 I took monthly distributions. So in effect I took double IRA distribution income in 2018. My federal tax liability for 2018 is about $27,000, where it normally would have been closer to about $12,000.
