Published: Apr 22, 2010 2:37 PM EDT

TALLAHASSEE, Fla. - Former Vice President Dick Cheney is endorsing Marco Rubio in Florida's GOP Senate primary, saying Gov. Charlie Crist can't be trusted to stand up to President Barack Obama's agenda.

It's the latest high-profile endorsement for Rubio. Cheney called him a strong conservative leader. As for Crist, Cheney said in a statement released by the Rubio campaign Thursday that "Charlie Crist cannot be trusted even to remain a Republican."

Crist is considering an independent run for the Senate seat. Cheney urged him to either remain in the primary or drop out, saying the only people who would benefit in a three-way race are Obama and Senate Majority leader Harry Reid. U.S. Rep. Kendrick Meek is the Democratic front-running in the race.