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Sen. Ted Cruz said this morning that if Donald Trump is elected president, it will end the Second Amendment in the United States.

Cruz argued that Trump has given money to Democrats - like John Kerry, Chuck Schumer and Harry Reid - for four decades, and would likely appoint a liberal justice to replace the late Antonin Scalia.

"We are one justice away from losing the Second Amendment. If you vote for Donald Trump, we will see the Second Amendment written out of the Constitution because one liberal justice will do that," he argued.

Trump said in an interview last month that the Second Amendment cannot be "tampered with" after President Obama announced new executive actions on guns.

In a new CBS poll, Trump leads Cruz by 22 points in South Carolina, with Marco Rubio in third place. But Cruz, who won the Iowa Caucus, emphasized that the survey was taken before Saturday's contentious debate.

Cruz said this morning that after the debate on Saturday night, Donald Trump's poll numbers have been "plummeting."

"The time for the circus is over. People realize, particularly with Justice Scalia's passing, that the stakes are serious [and] that we need a serious nominee who will defend the Constitution," said Cruz, adding he likes Trump personally, but that the billionaire has been a liberal his entire life.

Cruz vowed that he will filibuster any justice that Obama nominates.

Watch more above.

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