Rudy Giuliani will give a boost to U.S. Senate hopeful Marco Rubio on Monday — a Republican who’s running in a bitter primary against Gov. Charlie Crist, who has been famously reported to have double-crossed the former mayor in his presidential run.

In what strikes me as a clear case of settling scores, the Associated Press says Giuliani will appear with Rubio in Miami on Monday, and is expected to endorse him then.

Giuliani, in a statement released by Team Rubio, said, “Marco Rubio is one of the Republican Party’s true rising stars. He’s a bold leader who will bring common sense to Washington where it’s badly needed.”