Bennett said Thursday that it was clear after Super Tuesday that McCain had "won the Republican nomination fair and square."

Bennett had pledged his support to Romney but switched to McCain after the former Massachusetts governor suspended his campaign and called on his backers to unite behind the prospective nominee.

"Now, I call on Mike Huckabee to do the same," Bennett said. "John McCain deserves the time to unite the party and prepare for the battle in November rather than being distracted by a candidate that hopes lightening will strike even though the thunderstorm has since moved on."

McCain's advisers have pointed out that it is mathematically impossible for Huckabee to now garner enough delegates to win the nomination. McCain is a few hundred shy of the 1,191 needed to clinch the nomination and could surpass that mark next week after primaries in Texas and Ohio.