"Good ol' @SenSanders is always entertaining. Not a huge fan."
The patronizing tweet was directed at Bernie Sanders, the Vermont Senator who describes himself as a democratic socialist.
Luke Welch, a "New Media/Press Assistant" for Sen. Collins, soon tweeted: "Please disregard that tweet by Senator Collins, this was posted in error and doesn't represent her views."
Welch told Whispers he posted the tweet "inadvertently."
When Sanders' press secretary Michael Briggs was asked if he would like to comment, he replied: "I don't think so."