If you are a would-be immigrant who is inadmissible to the U.S. (as discussed in Inadmissibility: When the U.S. Can Keep You Out), you might be able to overcome this by applying for what's called a waiver of inadmissibility. In most cases, this is done on Form I-601, which you would submit to U.S. Citizenship and Immigration Services (USCIS), as discussed in this article.
(Note that there's a different form and discussion you'll want to turn to if you're looking for a provisional waiver of unlawful presence in the U.S., and this is your only ground of inadmissibility; the I-601A waiver.)
What, exactly, you will need to prove in order to receive the I-601 waiver depends partly on the reason you are inadmissible in the first place. For example:
For further detail, see USCIS's instructions to Form I-601.
Most types of I-601 waiver applications include the "extreme hardship" element mentioned earlier. In other words, the applicant would need to show, as part of receiving waiver approval, that a qualifying relative (a member of the immigrant-applicant's immediate family) is a U.S. citizen or permanent resident and that that person would suffer extreme hardship if the immigrant were to be denied U.S. entry or removed from the U.S., or if the whole family had to move overseas in order to be together.
In addition to the various standards, realize that the decision-making process for I-601 waiver applications is somewhat subjective. The ultimate decision will depend on the discretion of the immigration officer reviewing your application, and that officer's interpretation of your circumstances.
The chance of your application being approved also depends on the strength and quality of the evidence you submit. Adjudicators will review your evidence and balance the hardships you present with the existence of any aggravating and mitigating factors.
The term "extreme hardship" is not defined in U.S. immigration law. Consequently, the decision-makers have greater discretion to approve or deny I-601 waiver applications than they do with other U.S. immigration benefits. One of the most common reasons U.S. immigration authorities deny an I-601 waiver application is insufficient evidence of extreme hardship to qualifying U.S. relatives. Sometimes this is simply due to the applicant not having submitted enough convincing documentation.
No matter how sad your qualifying relative might feel if you were denied a visa or green card (or if he or she had to leave the U.S. to be with you), you can assume that every other separated family will feel the same. That's not going to be viewed as "extreme" enough.
You'll need to provide enough evidence something more with your application. If, for example, your relative would be forced to move to an unfamiliar country outside the U.S., you'd want to alert USCIS to the fact that your relative doesn't speak the language, has no other family or friends, and would perhaps lose his or her livelihood, or face particular health challenges. (Denials are more common in cases where the opposite is true, and the person will be heading to an ancestral country with a familiar language.)
The more documentary evidence you can provide, such as a letter from the family member's employer saying it would be impossible to continue the same job abroad, or a letter from a doctor saying a medical condition would be hard to treat, the better.
If your relative would remain in the U.S. without you, a denial is more likely if your relative is healthy and self-sufficient, and doesn't need your help taking care of other family members in the United States. The opposite is true if you can show, for example, that the non-citizen is the primary wage earner, but would lose that income, while the U.S. citizen staying behind would have to care for a child (perhaps a special-needs child) with no source of income.
The chances of your I-601 waiver application being denied might be higher if aggravating factors are present in your immigration, criminal, or other history. Aggravating factors include, but are not limited to, prior violations of immigration law, criminal charges, arrests, convictions, and marriage fraud. Any of these factors on your relative's record could also be viewed as aggravating. When you prepare your I-601 waiver application, it is important that you identify all aggravating factors that could weaken your application.
Keep in mind when preparing an I-601 waiver application that the cause of your inadmissibility may itself be an aggravating factor and negatively affect your chance of approval. Even if the law permits you to file a waiver application, your chances of success are less if you were found inadmissible for fraud or willful misrepresentation, or for criminal grounds.
If you have aggravating factors present, you will need to show a much higher level of extreme hardship for your qualifying relative. You will also want to submit evidence of mitigating factors. Mitigating factors can overcome aggravating factors, particularly if they are directly related.
For example, if you have a criminal background, evidence that you participated in a rehabilitation program is a mitigating factor that could strengthen your application. If you are inadmissible because of unlawful presence in the U.S., evidence that you acted in good faith and believed you were complying with immigration laws is a mitigating factor that could strengthen your application.
In the event that USCIS denies your waiver request, you potentially have the option to file a motion to reopen or reconsider, or submit a new application. Your chances of approval will not necessarily increase, however, unless you are able to figure out what went wrong the first time persuade a new decision-maker that your qualifying relative really would experience extreme hardship, or that you otherwise meet the standards for the waiver in question.
The level of discretion and subjectivity involved in adjudicating I-601 waiver applications means one can never guarantee a positive outcome. It's always a good idea to consult with an immigration attorney who has extensive experience filing waiver applications. It is through experience that attorneys can identify those factors that can make or break your application.