Republican presidential candidate Donald Trump explained to Greta Van Susteren tonight why he didn't correct a questioner at a New Hampshire town hall meeting last week who said that President Obama is a Muslim.

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"It's not my job to, frankly, defend the president," Trump said. "The president is capable of defending himself."

The GOP front-runner said he thought about speaking up, but decided not to.

"The fact is, this is the first time in my life that I didn't say anything and it was a big story," Trump said. "Usually, I have to say something. This was a case - in fact, people sort of smile about it - I didn't say anything and it became this massive story."

Trump added that he knows that Obama would never defend him.

"If somebody says something about me, Greta, he's not defending me. That I know for sure."

Trump suggested that this whole story led to Dr. Ben Carson's controversy surrounding his comments that he wouldn't support a Muslim presidential candidate.

Watch more above.

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