Your were right, and he says he'll never do it again, and references that he did before. I can respect someone making a mistake, if they acknowledge it was a mistake, but that Romney endorsement is not something I'l be forgetting.
http://www.nationalreview.com/corner/262446/demint-won-t-endorse-romney-unless-he-renounces-romneycare-katrina-trinko