Watch the Moment the Gloves Finally Came Off Between Trump and Cruz at the GOP Debate

During Thursday's GOP debate, Sen. Ted Cruz was forced to weigh in on his eligibility to run for president of the United States—a controversy Donald Trump has been vigorously fanning as the Canadian-born senator has risen in the polls.

Cruz's initial annoyance was palpable, but it was clear he was prepared for the "birther" issue to come up. Throughout the campaign, Cruz has avoided hitting back against Trump. But this was the moment the gloves finally came off.

"The Constitution hasn't changed," Cruz said. "But the poll numbers have. And I recognize that Donald is dismayed that his poll numbers are falling."

Watch the tense exchange below: