This week in an interview with ABC News political director Rick Klein, real estate mogul Donald Trump attacked the field of Republican presidential candidates with his harshest criticism reserved for the former Gov. Jeb Bush (R-FL).

Trump said of Jeb Bush, “He is stumbling. I don’t know, I don’t understand this man. He’s stumbling like he’s not even a smart person. On simple questions. What’s going to happen when it’s complicated? Honestly he doesn’t look happy. He doesn’t want to be doing what he is doing. I don’t know—is the family forcing him to do it? I call him the reluctant warrior. Perhaps warrior is not a good word, cause I’m not sure he is a warrior.”

On Senator Marco Rubio (R-FL), Trump said  “I was so disappointed when I looked at his answer on Iraq. It was such a stupid answer and such a foolish answer. And he’s got a lot of problems.”

Discussing Governor Scott Walker (R-WI): “I like him very much. I think he’s a good guy, but Wisconsin, as you know, is piling on debt over debt and that’s going to be, I think, a big problem for him.”

Commenting on his “friend,” Chris Christie, Trump said,  “I know him very well, he’s a friend of mine, but he’s got a lot of difficulties. He knows it better than anybody. So I don’t know if he’s running, but he certainly has a lot of difficulties with what’s going in New Jersey and with Bridgegate and with other things.”

He concluded with Hillary Clinton, saying, “What she’s done with the emails is unbelievable. I think the book, the cash, is a big problem for her. I think its going to end up being a big problem. I think she’s got some difficulties . I don’t think it’s going to be that easy for her.”

Follow Pam Key on Twitter @pamkeyNEN