The 42-year-old previously pleaded not guilty and denied sending the letters. He also denied a later charge that, while incarcerated, he tried to recruit someone else to send a ricin-tainted letter.
Dutschke has been jailed since April on charges of sending the letters to Obama, Republican U.S. Sen. Roger Wicker, and a Mississippi judge. The judge was the only one to receive a letter, though she was not harmed. The letters to Obama and Wicker were intercepted.
Prosecutors recommended a 25-year sentence. That sentence would run concurrently with any sentenceDutschke would face in state court, where he's facing unrelated fondling charges.