(UPDATED) Rick Santorum, the candidate who was lately seen as the most serious challenger to Mitt Romney for the presidential nomination, will drop out of the Republican race for the nomination. These sources have confirmed to Breitbart.com that Santorum’s withdrawal will come within the next few hours.

Mitt Romney will become the Republican nominee. The campaign now moves into its next stage: the general election.

Video of Santorum's valedictory speech is below.

ON BREITBART TV