In an appearance on CNN's Situation Room with Wolf Blitzer, real estate executive and reality television personality Donald Trump called U.S. President George W. Bush "probably the worst president in the history of the United States."

A transcript of the exchange follows:

TRUMP: Well, I think Bush is probably the worst president in the history of the United States, and I just don't understand how they could have lost that election.

BLITZER: Let's get back to that in a moment.

Let's talk about Rudy Giuliani, the former mayor of New York.

TRUMP: Very, very talented, smart, tough, very formidable in every way. And I think, if it's him and Hillary, it's going to be a hell of a tough race.