The following is not legal advice and is for general informational purposes only. Please consult a qualified immigration lawyer for advice on your specific situation.
People legitimately marry for many reasons, such as: for love, to start a family, for money, convenience, power, prestige, family and social acceptance. However, when a US citizen marries a foreign-national who applies for permanent residence through marriage, the USCIS will determine the validity of the marriage for immigration purposes.
If the marriage is valid at inception, it is valid for immigration purposes. The test is whether the bride and groom intended to establish a life together. If a marriage was knowingly entered into for the purpose of evading US immigration laws and the person knew or had reason to know of the immigration laws there could be immigration, civil and/or criminal consequences.
Some facts to keep in mind for an alien who wishes to obtain permanent residence through marriage to a US Citizen: (1) cohabitation and consummation are not absolute requirements, (2) homosexual marriages are not valid, and (3) postoperative transsexual marriages are recognized.
A foreign national who applies for permanent residence through marriage will be granted conditional residence status unless the marriage is more than two years old at the time of granting immigrant status. A conditional resident and his or her spouse should petition the USCIS to remove the condition within 90 days before the second anniversary of conditional residence. If a joint petition cannot be filed, in certain situations, the alien may apply for a waiver.
For almost all marriage cases, the USCIS will require the spouses to attend an interview at the district office (if the alien is in removal proceedings, the case will be heard by an immigration judge). A sham marriage is illegal and if discovered, could become a true nightmare for both spouses involved. However, if an alien is fortunate enough to truly fall in love with and marry a US Citizen who is willing to apply for him or her, it is among the fastest ways to become a legal permanent residence.
As with all areas of immigration, there are many quirks and restrictions that the parties need to be aware of prior to filing the petition and application. Despite the strong temptation to file the case oneself, I strongly recommended that the alien be represented by qualified counsel whenever possible.