Ted Cruz Goes After Donald Trump's Mom in Birther Battle at GOP Debate

PHOTO: Republican presidential candidates Ted Cruz and Donald Trump during the Fox Business Network Republican presidential debate at the North Charleston Coliseum on Jan. 14, 2016, in North Charleston, S.C.PlayChuck Burton/AP Photo
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In a heated back-and-forth at tonight's Republican debate, Sen. Ted Cruz directly responded to Donald Trump’s questioning of his eligibility to be president because he was born in Canada.

“At the end of the day, the legal issue is quite straightforward,” Cruz said tonight. “I would note that the birther theories that Donald has been relying on, some of the more extreme ones insist that you must not only be born on U.S. soil but have two parents born on U.S. soil.”

Cruz has said he is a U.S. citizen because his mother was an American citizen at the time of his birth.

Cruz said if he was to be disqualified as president, so would Trump.

“Donald’s mother was born in Scotland. She was naturalized,” Cruz exclaimed.

“But I was born here,” Trump fired back.

Cruz claimed Trump's birther attacks stemmed from his rising poll numbers in Iowa.

Trump acknowledged that he was bringing up the issue “because [Cruz] is doing a little bit better.”

But Trump warned: “There is a big question mark on your head. And you can't do that to the party....you have to have certainty.”

Trump told Cruz that Democrats would raise the citizenship issue in the general election. "You have great constitutional lawyers that say you can't run," Trump said.

“I'm not going to be taking legal advice from Donald Trump,” Cruz retorted.