Will Jeb Bush, a former Florida governor, try to become the third member of his immediate family to run for president? His brother calls it “a tossup.”

In an interview with CBS broadcast Sunday on “Face the Nation,” former President George W. Bush said his brother was “wrestling with the decision” about whether to undertake a presidential campaign in 2016. The former president said he put the chances of his brother doing so at “50-50.”

“I know this about Jeb,” Mr. Bush said. “He is not afraid to succeed. In other words, I think he knows he could do the job. And nor is he afraid to fail.”