In the past few days, there has been renewed buzz on the Internet about the presidential eligibility of Texas Sen. Ted Cruz. Cruz has only been in the Senate for about 60 days and does not appear to be behind any of the talk. But he has certainly been in the news in recent days, and in response to a request for comment, his spokesman, Sean Rushton, sent me this note:

Sen. Cruz is a U.S. citizen by birth, having been born in Calgary to an American-born mother. He is focused entirely on his new role in the Senate, and on working every day to represent Texas and defend conservative principles in the Senate.

Any talk about Cruz follows years of discussion about birthplace and presidential eligibility involving President Obama, Sen. John McCain, and Sen. Marco Rubio. The bottom line in the case of Cruz, who was born in Canada in 1970, is that his father was an immigrant from Cuba and not a U.S. citizen at the time of young Cruz’s birth, but his mother was born and raised in the United States. The law in effect then, and now, made Ted Cruz a U.S. citizen at birth. Although the drafters of the Constitution did not define what they meant when they required an American president to be a “natural born citizen,” it is generally thought that “citizen by birth” is the best modern-day equivalent. On that basis, Cruz appears entirely eligible — if he ever chooses to pursue the White House.

Last year, I wrote about citizenship law, focusing on the case of Rubio, who was born in the United States and about whom there is no question of presidential eligibility. Some of that article also applies to Cruz:

The Constitution specifies that a president must be a “natural born citizen” of the United States, but it does not define the term. The Supreme Court has never clarified the issue, but there is a law, 8 U.S. Code 1401, that spells out in detail who is a citizen. The law uses the phrase “citizens of the United States at birth” and lists categories of people who fit that description. First, there are people born inside the United States. No question about that; their citizenship is established by the 14th Amendment. Then there are the people who are born outside the United States to parents who are both American citizens, provided one of them has lived in the U.S. for any period of time. And then there are the people who are born outside the United States to one parent who is a U.S. citizen and the other who is an alien, provided the citizen parent lived in the United States or its possessions for at least five years, at least two of them after age 14.

That last category covers Cruz, making him a citizen at birth. Last year, Theodore Olson, the former Bush solicitor general who successfully defended John McCain in a 2008 lawsuit alleging McCain was ineligible to be president, told me, “My conclusion would be that if you are a citizen as a consequence of your birth, that’s a natural-born citizen.” That would likely be the conclusion of any challenge to Cruz’s eligibility, as well.