Peter Thiel was born in Germany, acquiring American citizenship only later, and is presumably not eligible to be president of the US on that basis.
1. https://en.wikipedia.org/wiki/Ted_Cruz#Citizenship 2. https://en.wikipedia.org/wiki/John_McCain#2008_presidential_...
Interestingly this definition is commonly agreed upon but not written down in the constitution, and the Supreme Court has never taken up this challenge.
More concisely, it is hubris plus gumption minus diligence.