American Indians were only made into US citizens circa 1980. I believe President Carter signed the law making them citizens.
The Indian Citizenship Act was passed in 1924.
Native Americans became citizens in the 1920’s. Native Americans were not considered citizens because they did not owe their allegiance(subject) to the U.S.. They were of course subject to the laws of our nation(enforced by dept. of Indian affairs and U.S. military).
SUBJECT: One who owes allegiance to a nation
SUBJECT: TO BE HELD ACCOUNTABLE TO
While Native American were accountable to American laws( subject), they were not SUBJECTS of the nation.
The 14th amendment requires that citizens be born subject(owes allegiance to) to the U.S., and this can only be by birth to American citizens.
If Rubio’s parents had legal status to be in the U.S. Marco is a citizen, but if they were not U.S. citizens at the time of his birth , he is NOT considered Natural Born.