If you are staying in Mexico for less than six months, you should apply for a FMT (Short-Term Non-immigrant) visa.
You should be OK, if you have a valid passport.
You should contact the American embassy in Mexico for legal advise:http://www.usembassy-mexico.gov/
He or she could, but his or her partner must make the appropriate arrangements so that she or he acquires the US citizenship. Namely, contacting the American embassy in Mexico and begin such legal process.
In order to fight for paternal rights in the USA. from Mexico, a Mexican citizen should have a lawyer in the USA. representing his or her interests. It may even be best to make a visit on the day of the court appearance. Hire a lawyer and check with your lawyer.
If your parents were US citizens when you were born- you automatically are a US citizen. The US embassy should have given you documents stating your citizenship during the time you were born. This is what my sister did.
You should look up "How to become a citizen in the UK". It should be the same.
The word citizen does not need to be capitalized.
in order to become a us citizen you must live as a permanent resident for five years then apply If you're not citizen by birth or born to US citizen parent then you can apply through naturalization process. You need to fill in the Form N-400 for this purpose. Basic criteria for applying is you should be 18 years and older and should be a permanent resident for a minimum 5 year period in US. If married to a US citizen the minimum period is 3 years. You will need to pass a citizenship test where you must answer 6 out of 10 questions correct
As a citizen of the Marshall Islands, you don't need a visa to enter Mexico, and you can stay up to 180 days without further immigration requirements. You should provide, however:A valid, machine-readable passport or an emergency/temporary passport.Return/onward tickets.Failing to provide any of these can result in a refusal of entry.
It seems like the easiest thing is for the two parents to figure it out. The non-citizen parent should definitely be upfront and honest in his dealings with the other parent to keep visitation going.
why should a state interfere in personal matters of citizen
If such Canadian citizen wants to live in Mexico, he/she needs to begin the immigration and naturalization process. Most problems have to do with the language barrier, different traditions and beliefs. However, if such person is open-minded, it should be a pleasant experience to live in Mexico. See related questions for further detail.