Former President George W. Bush told CBS' Face the Nation that it's a toss-up as to whether his brother, former Florida Gov. Jeb Bush, will run for president in 2016. New Jersey Gov. Chris Christie is also mulling a run at the White House and has close ties with the Bush family.

Gov. Chris Christie (Bryan Thomas, Getty Images)

In the May edition of Townsquare Media's Ask the Governor program he admitted it would be tough squaring off against Jeb Bush in a Republican presidential primary.

"It would be stressful because I consider Jeb a friend and he's been a wonderful friend to me especially during (Superstorm) Sandy and the aftermath, and gave me some extraordinary advice," Christie said in May. "It would be stressful. You like to run against people that you don't like, not run against people that you do like and respect so, of course it would be stressful if you have a relationship."

Jeb Bush's son, George P. Bush, has said publicly that it's likely his father will run, but Jeb's mother Barbara has also said the country has seen enough Bushes running for president.

"I think it's 50-50," George W. Bush told Face the Nation, when asked about a Jeb Bush presidential run.

On Ask the Governor in May Christie said he takes Bush at his word that he hasn't made up his mind yet. Christie has repeatedly said in recent weeks that he hasn't made up his mind either.

"In the end, everybody is going to make their own decisions, myself included, about what they think is best for them, and what they think is best for our party, and what we think is best for the country," said Christie in May.

See the video below of former President George W. Bush on CBS' Face the Nation.