"[S]everal of your fine stalwart membership then referred to me as a 'Natzi pig f—er'"

Simpson called for a spirit of cooperation in the letter, but did so using colorful, occasionally coarse language. The letter to Max Richtman, the president and CEO of the National Committee to Preserve Social Security and Medicare, who criticized Simpson earlier this week in a letter published by Politico, swings from sarcasm to bluntly expressed frustration and angry to seemingly grudging respect.

“I spent my entire public life trying to put Social Security back together and make it solvent for over 75 years. Why don’t you help me?” Simpson wrote in the letter, obtained Friday night by ABC News…

“I didn’t hear a peep out of your organization either – except when I got a whole ration of mail from your people — they said they were ‘urged’ — obviously stimulated by you (thinking I was still in the Senate) and several of your fine stalwart membership then referred to me as a ‘Natzi pig f—er,’” he wrote.