Eg to become a Russian
He needs to be a US citizen in order to become President but does he need to stay one throughout the full term or does the rule only apply to people who can be made President in the first place?
It doesn’t say “eligible to be elected,” but eligible to the office. I would presume he would have to stay a citizen to remain in office after election.
But even if that were not so, it would be a political impossibility. The President would either be impeached, or would lose any political support he had.
Interestingly enough, this almost happened one time.
In 1860, Stephen Douglas got the Democratic Party’s nomination for President (or one of them depending on your view of things). In an effort to appeal to southern voters, Herschel Johnson of Georgia was nominated as his running mate.
Douglas and Johnson, of course, lost the election. But suppose they had been elected. Secessionists in the south said they planned on seceding if Lincoln or Douglas was elected. So we’ll take them at their word and say they seceded as they did historically. Herschel Johnson opposed secession but ended up going with Georgia when it seceded.
The timing is admittedly a little muddled here. Georgia seceded from the United States on January 18. Johnson would have been formally elected Vice President by the Electoral College on December 17 but he wouldn’t have been inaugurated until March 4. But as Vice President Elect it seems possible that Johnson might have hesitated before deciding to go with the Confederacy. Or perhaps the secessionists might have moved slower in the face of an impending Douglas presidency rather than a Lincoln one.
The next significant date is June 3, 1861 which is when Stephen Douglas died of cancer, three months into his term of office. And at that point, if Johnson were Vice President he would presumably have become the President of the United States despite having declared himself a Confederate citizen.
I don’t think the current President is eligible for Kenyan citizenship, but if he were, acquiring a second citizenship would not legally disqualify him from continuing to be President, since he would continue to be a natural-born citizen of the U.S. Similarly (and hypothetically), Mitt Romney being a Mexican citizen or John McCain being a Panamanian citizen would not have disqualified them from holding office if elected, since they were both natural-born citizens.
In order for a US President to “change” citizenship as per the OP, he would first have to renounce his US citizenship. As Cecil describes, the procedure is difficult and requires leaving the country. Again, if a sitting President somehow attempted this he would be impeached long before he had completed the process.
You don’t have any control over whether sovereign nations consider you a citizen or not.
Russia could tomorrow proclaim Barack Obama is now a Russian citizen, what can Obama do about it? Not a damn thing.
If one of your parents is a citizen from a jus sanguinus practicing country you might be considered a citizen by that country, there is nothing you can do about foreign laws.
This is a point that the birthers almost got right. Obama had Kenyan citizenship as a child, through his father. (Actually, he started as a British citizen.) Kenya, however, does not recognize dual citizenship, and in order to keep his Kenyan citizenship, he would have had to renounce his U.S. citizenship and swear allegiance to Kenya. He didn’t do so, and hence lost any opportunity to become president of Kenya.
They do now, I think. In 2011, they passed a new citizenship law allowing dual citizenship. Prior to that point, the child of Kenyan parents who also had citizenship in another country had to choose his citizenship by the age of 23, or would no longer be considered a Kenyan citizen by birth.
Here’s the revised act:
http://www.nairobi.diplo.de/contentblob/3356358/Daten/1788002/d_KenyanCitizenship_No12_of_2011.pdf
Something similar happened to Ted Cruz, who was apparently quite surprised to find that Canada considered him a Canadian citizen just because he was born there. He got them to recognize his renunciation.