Though the older Paul seems unready to admit defeat, the younger Paul, Kentucky Sen. Rand Paul, has thrown in the towel, in the form of an endorsement for none other than Mitt Romney.

The endorsement came in an appearance on "Hannity," a little less than 24 hours after the elder Paul acknowledged in an email that his delegate total is "not enough to win the nomination."

Romney embraced the endorsement in a press release, calling Rand Paul a "leading voice in the effort to scale back the size and reach of government and promote liberty."