Robert Frank Ackerman, 45, now faces up to five years in a federal prison.
As part of a plea agreement with prosecutors, Ackerman admitted he had threatened to travel to Washington, D.C. to kill the president.
The threat was made in Kermit, TX during an argument over Obama's health care policies on May 7, 2010. Witnesses who heard him said they decided to go to the authorities after Ackerman suddenly left town. The Kermit Police Department passed the matter to the Secret Service.
Ackerman was arrested in connection with a bank robbery in California 10 days after making the threat.