I Somehow Always Thought That Foreign Spouses Of US Citizens ...

[BEZARK]

... automatically or easily became US citizens, or at very least permanent residents.

There is a big Army fort here, and lots of Korean wives.  (And good Korean restaurants)

[Lobo]

Yes, a foreign spouse of a U.S. citizen may be eligible for U.S. citizenship through naturalization if they meet certain requirements:

• Marriage

  The spouse must have been married to their U.S. citizen spouse for at least three years before filing their application
• Permanent residency

  The spouse must have been a lawful permanent resident (LPR) in the U.S. for at least three years before filing their application
• Residence

  The spouse must have lived in the same state or USCIS district as their place of residence for at least three months before filing their application 

  USCIS

  Spouses of U.S. Citizens Residing in the United States - USCIS

  The spouse of a U.S. citizen who resides in the United States may be eligible for naturalization on the basis of his or her marriage. The spouse must have continuously resided in the United States after becoming a lawful permanent resident (LPR) for at least 3 years immediately preceding the date of filing the naturalization application and must have lived in marital union with his or her citizen spouse for at least those 3 years.

  USCIS

  I am Married to a U.S. Citizen | USCIS

  Nov 18, 2020

  Nolo

  How Long Does It Take to Get U.S. Citizenship by Marriage?

  First, let's get one important thing straight: Marriage to a U.S. citizen makes someone eligible for U.S. lawful permanent residence (a "green card"), not for U.S. citizenship. (At least, not in the short term.) Having a green card for a certain number of years can make the person eligible for U.S. citizenship. But it's a two-step process, at a minimum. In short, even if the U.S. citizen husband sponsors the immigrant, receiving approval from the U.S. government doesn't turn the immigrant into a U.S. citizen right away.

After becoming an LPR, the spouse should file Form I-485, Application to Register Permanent Residence or Adjust Status, as soon as possible. If they are granted permanent residency before the second anniversary of their marriage, they will receive a two-year conditional green card. If they are granted permanent residency after the second anniversary, they will receive a 10-year green card without conditions. 

The process of applying for citizenship through marriage can take at least two steps and can take six to eight months on average. However, Section 319(b) of the law allows some applicants to apply for naturalization without meeting residency requirements. This can be helpful for foreign-born spouses who may have difficulty meeting the three-year residency requirement due to overseas assignments.