WASHINGTON -- Within an hour of former Florida Gov. Jeb Bush backing out of the GOP presidential primary, former Sen. Norm Coleman said he was shifting support to Florida Sen. Marco Rubio.

Coleman said in January he was backing Bush. He had previously been running Sen. Lindsey Graham's super PAC. Graham was a presidential hopeful last year, but suspended his campaign in January.

Late Saturday, Coleman said:

"Wish Bush out, I'm clearly on Rubio's team. I'm not sure whether that helps or hurts. I thought Jeb was the most qualified to be president," he said. "But Rubio clearly is our best hope and most qualified to be commander in chief with Jeb out of the race."

Rubio and Texas Sen. Ted Cruz were battling for second place after Donald Trump won South Carolina's Republican primary Saturday.