Republican Iowa Gov. Terry Branstad says he's unsure presidential candidate Newt Gingrich has the discipline and focus to be president.

In an Associated Press interview Thursday, Branstad was asked if the former House speaker, who is leading in Iowa polls, had the discipline to be president.

Branstad said of Gingrich, "Whether he has the discipline and the focus, I don't know."

Branstad says he probably won't endorse a candidate before the Jan. 3 caucuses in Iowa.

Branstad describes the Republican race in Iowa as volatile and says that missteps count in the final days.