Rep. Connie Mack IV got a major Florida endorsement in his run for the Republican Senate nomination Wednesday.

Former Governor Jeb Bush endorsed Mack for Senate, calling Mack "the principled conservative that the people of Florida deserve representing them in the U.S. Senate."

Mack is one of four Republicans running in the August primary, and is considered a frontrunner in the race. The winner of the primary will go on to run against incumbent Sen. Bill Nelson in November.

Bush's endorsement is a big feather in Mack's cap. Bush is still considered an important figure in Florida politics, and a popular governor. His name is continually mentioned as a potential running mate for presidential candidate Mitt Romney, though Bush denies that he is in the running.

Running against Mack is former Sen. George LeMieux, former Congressman Dave Weldon, and Col. Mike McCalister.

Full statement from former Gov. Jeb Bush:

“Connie Mack is the principled conservative that the people of Florida deserve representing them in the U.S. Senate. Connie has the courage, conservative values, experience and determination to confront the tough issues facing our nation. We must return conservatives to the majority in the U.S. Senate.  Connie is the person Floridians need in Washington working with Senator Marco Rubio to reduce our national debt and limit out-of-control spending.”