The process of helping a spouse immigrate is much easier for citizens than green card holders. That's partly because a visa is immediately available to the spouse of a citizen (who is an 'immediate relative,' in immigration law terms). The combination of your status as a U.S. citizen and the fact that your spouse entered the U.S. with inspection (on a visa) as opposed to having crossed the border or otherwise evaded inspection by immigration officials, gives your spouse an important procedural right: to 'adjust status' in the U.S., that is, to file his or her green card application at an office of U.S. Citizenship and Immigration Services (USCIS) and attend his or her interview at a local USCIS office. All of this can be done regardless of the length of time the visa was expired, and without leaving the U.S. for a U.S. consulate. (In fact, you should avoid at all costs having your spouse leave the U.S. until receiving the green card, for reasons of the 'three- and ten-year time bars' described next.) Contrast that with the situation faced by spouses of lawful permanent residents. They are able to start the immigration process as soon they're married, by filing USCIS Form I-130, but that only puts the foreign-born spouse on a waiting list. Several years might then go by, during which the foreign-born spouse will be accruing 'unlawful presence' in the United States and could be picked up and deported at any time. Worse yet, when the wait is over and it's time to apply for a green card, the immigrating spouse will NOT be able to adjust status, but will have to leave the U.S. to attend an interview at a U.S. consulate. There, as punishment for time spent in the U.S. unlawfully, the spouse can be barred from return for three or ten years.