, filed Thursday by Newton Boris Schwartz Sr., raises legal uncertainty about whether Cruz qualifies for the constitutional requirement that a president be a "a natural-born citizen" because he was born in Calgary, Alberta.
Cruz was conferred American citizenship at birth because his mother is an American citizen, and legal experts have largely agreed that would qualify him for natural-born citizenship. The Texas Republican also had Canadian citizenship until he renounced it in 2014.
The Cruz adviser told CNN that the belief within the campaign is that the case -- which the adviser described as "non-serious" and "ridiculous" -- will not have standing, because there is no harm that can be proven.
And the campaign believes Cruz "put that to bed last night," referring to his passionate statements on the matter in a rebuttal to Donald Trump
at Thursday's Republican debate.
"The facts and the law here are really quite clear," Cruz said, before suggesting that by Trump's own logic, the billionaire himself would be disqualified because his mother was a native of Scotland.
"But Donald," he said to rising applause, "I'm not going to use your mother's birth against you."
The adviser added that those who continue to bring this up can go ahead and put their "dunce hat" on.
The legal question, though, might not be as easy to sideline.
Harvard law professor Larry Tribe
, a liberal who counts Cruz and President Barack Obama among his former students, has frequently expressed doubt over Cruz's legal argument.
After being named and scorned during the debate on Thursday, Tribe said again in an interview on "Anderson Cooper 360" later in the evening that the issue represented "a serious cloud" hanging over the senator's candidacy.
"It has to be taken seriously," Tribe said. "It's not just a matter of coming up with great talking points or winning some debate. I think he does a disservice to the Constitution and the country when he thinks he can slide his way, slip slide his way around this serious constitutional issue."