“.. Resort must be had elsewhere to ascertain that. “
Right, and here’s the most recent “elsewhere” (law):
“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.”
more: http://nation.foxnews.com/sen-ted-cruz/2013/03/11/spokesman-senator-cruz-us-citizen-birth
Citizen yes, if his parents filed for a CRBA at the time, or was he naturalized at a later date?
Natural born citizen eligible to be President, no.