One of these factors is the past immigration history of the illegal person. Factors such as how this person originally entered the United States combined with additional factors such as if there has ever been any paperwork filed on their behalf.
If the person entered the country illegally, such as without a valid visa, then his or her status opportunities will be severely limited. If the person entered the country legally but has overstayed their visa, then this presents an entirely different situation. However, it is worth noting that just because someone has married a legal U.S. Citizen does not automatically grant him or her U.S. Citizenship, nor does it make him or her a legal resident of the United States.
Marriage does not automatically produce a green card, which is permanent U.S. Residence status. Aliens who have entered the country illegally will have the most difficulty claiming such status. If an illegal person has spent more than six months in the U.S. After an illegal entry, their penalty is three years outside the U.S. Aliens who have entered legally will not have this problem.
It is extremely important to consult with a licensed United States immigration attorney before doing anything. Seeking professional advice is always the best start. There are a number of sites where additional information can be obtained on this subject. A good website to check for this information is US Immigration Lawyers.com. Here you will find the answers to many of in-depth questions that you may be concerned about.