I just learned that prior to 1922, if an American women married an immigrant who was not naturalized, she automatically lost her citizenship. And later, if her husband was naturalized, her citizenship was NOT restored. She must then go through the process of being naturalized herself. Note that if an American man married a non-citizen, he was still a citizen and in fact he could ask for and get his wife naturalized with almost no questions asked.
This all changed in 1922 when Congress passed the 'Cable Act' which restored citizenship to American women who had lost it when they married an immigrant. Note that this was the same year that Congress passed a law that recognized Native Americans as US citizens.
http://en.wikipedia.org/wiki/Cable_Act
This is of personal interest to me as my maternal grandmother, who was born in Michigan, married my grandfather in 1916, who had immigrated from Belgium in 1913. Now I know he was eventually naturalized as he was always telling us how important it was to vote, but if he came here in 1916, it's unlikely that he had been naturalized in only three years. Now I can't recall anyone in the family ever talking about this, but I have asked my oldest cousin, who's a few years older than I am, if she had ever heard anything about this

OCU