[[He filed suit to prevent the Secretary of State from carrying out and enforcing the residency requirement claiming that it violated due process under the U.S. Constitution. The U.S. District Court for the District of Columbia agreed with Mr. Bellei and ruled that § 301(b) was unconstitutional.
The State Department appealed and the U.S. Supreme Court reversed the lower court ruling holding that the citizenship clause of U.S. Constitutional Amendment XIV did not apply to citizenship by birth abroad to an American parent. Further, that Congress’ imposition under § 301(b) of a condition subsequent to citizenship was not unreasonable, arbitrary, or unlawful.]]
The Bellei case it seems is about whether a person with dual citizenship has requirements they must meet in order to remain a US citizen- The lower court agreed with Bellei that citizens do not- but the supreme court stepped in and said- essentially, ‘Sorry- but citizens do have requirements in order to remain citizens, and Bellei did not meet those requirements- therefore Mr. Bellei loses his citizenship’
[[The statute governing Cruz is: 8 U.S.C. Sec. 1401:
“The following shall be nationals and citizens of the United States at birth:
g) a person born outside the geographical limits of the United States and its outlying possessions of parents one of whom is an alien, and the other a citizen of the United States who, prior to the birth of such person, was physically present in the United States or its outlying possessions for a period or periods totaling not less than five years, at least two of which were after attaining the age of fourteen years.”]]
Same link
[[Note: You may already be a U.S. citizen and not need to apply for naturalization if your biological or adoptive parent(s) became a U.S. citizen before you reached the age of 18. For more information, visit our Citizenship Through Parents page.]]
https://www.uscis.gov/us-citizenship/citizenship-through-naturalization