Sen. Tim Scott is expected to officially endorse Sen. Marco Rubio on Tuesday. | AP Photo Marco Rubio to score big endorsement from Tim Scott

DES MOINES -- Marco Rubio is expected to secure the widely coveted endorsement of South Carolina Sen. Tim Scott on Tuesday, according to three sources.

Scott, the only black Republican is the U.S. Senate, will be Rubio’s second major congressional endorsement in the state; the Florida senator has also secured the backing of South Carolina Rep. Trey Gowdy. Rubio is expected to make a major play in South Carolina’s Feb. 20 primary.


The endorsement comes at a time of growing anxiety in establishment GOP circles, with many in the party hierarchy worried that Rubio, John Kasich, Jeb Bush, and Chris Christie are dividing the establishment vote. There is hope among Rubio’s backers that Scott’s support, coupled with at least a third-place finish in the Iowa caucuses, will help him unite the party.

Spokespersons to Rubio and Scott did not respond to requests for comment.

Scott’s endorsement had been sought by several candidates, including Bush. Bush, who has the backing of South Carolina’s other senator, Lindsey Graham, is expected to have a poor showing in Iowa and is spending Monday evening in New Hampshire. So, too, are Kasich and Christie.

Sources close to Rubio say he’s likely to use the endorsement to make the argument that he’s the most electable candidate in the race and that it’s time for Republicans to rally around a candidate who can defeat the Democratic nominee in November.

Rubio is slated to appear before supporters Monday night at a Marriott in Des Moines.

