** LEGAL UPDATE **
According to a Policy Alert from U.S. Citizenship and Immigration Services (USCIS), green card holders (lawful permanent residents) who make use of the exception allowing them to apply to naturalize after three rather than five years based on having been married to and living in marital union with a U.S. citizen that whole time face new requirements with regard to the marriage ending.
They must maintain their married and living-together status not only through filing of the Form N-400 application for naturalization (as was the previous policy), but through the swearing-in or oath ceremony that makes them an actual U.S. citizen.
This can be a significant time difference. After filing a Form N-400, most applicants wait several months for their interview at a USCIS office. Applicants who fail either the English or the civics portion of the exam might have to return for a second interview.
After finally receiving USCIS approval, the person must in most cases await a swearing-in or oath ceremony appointment, which might also be scheduled several weeks into the future.
All told, this means that couples who are in rocky marriages and counting the days until the immigrant becomes a U.S. citizen and they can separate or divorce should probably add an extra year to the calculation.
Effective Date: October 12, 2018