Ted Cruz Goes After Trump's "Scottish" Mom In Heated Birther Battle

The Texas senator may have taken some time to respond to Trump’s infamous “birther” accusations – but when he did, he certainly packed a punch.

The early portion of Thursday night’s Republican presidential debate was dedicated to the much-anticipated showdown between Ted Cruz and Donald Trump, as they sparred extensively over Cruz’s birth in Canada.

“Back in September, my friend Donald said he had his lawyers look at this in every which way. There was nothing to this birther issue,” the Texas senator said early on in the debate, amid cheers and whistles from the crowd. “Since September, the Constitution hasn't changed, but the poll numbers have. And I recognize that Donald is dismayed that his poll numbers are falling in Iowa.”

Cruz then said that if they actually rely on Trump’s “you have to have two parents born on U.S. soil to be eligible” theory, then Marco Rubio, Bobby Jindal and even Trump himself would be disqualified since his mother was born in Scotland.

“On the issue of citizenship, Donald, I'm not going to use your mother's birth against you,” Cruz retorted.

Of course, Trump being Trump, had to respond to Cruz’s quip by touting his rising poll numbers. However, when he cited a recent NBC News/Wall Street Journal poll that gave him a 13-point national lead over his opponent, the business mogul got booed by the crowd.

 “You have a big lawsuit over your head while you're running,” the Republican frontrunner said, adding that the audience was booing Cruz, not him. “And if you become the nominee, who the hell knows if you can even serve in office.”

The senator then earned laughter by joking about naming Trump as his vice-presidential nominee, so that even if he were disqualified from the presidency, the former reality TV star would take over at the top of the ticket.

Cruz's birther issue has become a major source of contention and point of attack in the Republican presidential race. As Cruz's poll numbers have increased, Trump (a notorious birther) has questioned the Canadian-born candidate's eligibility to run for president as an obvious way of disqualifying his rival. 

Watch the Republican presidential hopefuls’ epic smackdown in the video above.

Recommended: 'Freedom Kids' Perform Cringeworthy Song at Trump Rally