Republican Sen. Ted Cruz has had plenty to say about immigration and immigrants becoming U.S. citizens during his presidential bid.
"I have never supported amnesty," Cruz said.
"You see what happened in San Bernardino when you're letting people in and the FBI can't vet them," Cruz said.
But questions about Cruz's own U.S. citizenship have persisted. Here's why:
Ted Cruz was born to an American mother and a Cuban father ... in Canada.
The Constitution says that one requirement for becoming POTUS is that a candidate must be a "natural born citizen," among other things. But what exactly is a "natural born citizen?" Thing is, it isn't defined in the Constitution.
The Congressional Research Service released a report in 2011 on the qualifications for president, focusing on natural born citizenship. It supported the idea that natural born citizenship means you're a citizen at birth.
If that's the case, Cruz being born to an American mother would make him a U.S. citizen. But others, like this constitutional-law professor and legal historian, argue a natural born citizen is someone born in the United States. In that regard, Cruz is not a natural born citizen.
Even Republican Sen. John McCain faced his own birther criticism when running for president because he was born in the Panama Canal Zone; he said this about Cruz's citizenship: "I think it's worth looking into."
So, how exactly do we figure this out? We don't, but the Supreme Court can. Problem there is the Supreme Court has never directly defined the term "natural born citizen."
Until it does, the question of natural born citizenship is likely to remain, for some, unsettled.
This video includes images from Getty Images.