No one gets a U.S. green card or visa or other form of U.S. entry without first proving that they are not "inadmissible" to the United States. It doesn't matter if you have married a U.S. citizen, have a job waiting for you, or are even standing at the border with a visa in your hand.
The reason is that immigration laws attempt to protect U.S. society from people with histories of criminal or terrorist activities, drug abuse, infectious medical problems, or certain other characteristics. Applicants who are found to be inadmissible will, unless they fall under an exception or successfully apply for a waiver (legal forgiveness), not be allowed any sort of visa, green card, or U.S. entry. Exceptions do exist, however, and not every type of applicant is subject to every ground of inadmissibility. (See 8 U.S.C. § 1182.)
Below you'll find a short, summary list of the categories of inadmissibility that most commonly result in applicants being denied a visa or green card. (The list contained in the actual law is much longer and more detailed, including exceptions in some instances.) The list also mentions whether you can apply for a waiver.
Basis of Inadmissibility |
Is a Waiver Available? |
A communicable disease like tuberculosis or pandemic flu or other diseases noted by the Centers for Diseases Control (CDC) including COVID-19. (Note: HIV was once on this list, but no longer) |
Yes |
A physical or mental disorder of public health significance |
Yes |
Drug abuse or addiction |
No |
Drug trafficking record |
No |
Conviction of crime involving moral turpitude |
Yes |
Multiple criminal convictions |
Yes |
Intentions or history of committing espionage or terrorism |
No |
Prostitution |
Yes |
Participation in Nazi persecution or genocide, torture, or extrajudicial killings |
No |
Failure to receive all the vaccinations recommended by the U.S. government |
Yes |
Violations of U.S. immigration laws |
Yes |
Likelihood of becoming dependent on public assistance or welfare |
No |
When you submit your application to the U.S. government for a visa or green card, you will be asked to answer various questions about your background, especially your criminal and immigration record. Green card applicants must actually have a medical exam done, and have their fingerprints taken and then checked against various law-enforcement databases.
Most often, it's not until your visa or green card interview that the immigration authorities will look at your application answers and the results of your medical exam or background check.
But if you appear to be inadmissible, you won't necessarily be denied right away. The immigration officer may give you a period of time in which to prove that the finding was wrong, or to apply for a waiver (if one is available for your type of inadmissibility).
But your problems aren't necessarily over. An officer at the U.S. border (with Customs and Border Protection, or CBP) can also decide that you're inadmissible, if information comes to light that wasn't revealed in your earlier application. If, for example, you are entering on a tourist visa but your suitcase contains a wedding dress and the application form for a U.S. green card, the border officer could conclude that you are attempting a misuse of your tourist visa and secretly planning a permanent stay, and thus deny you entry. You would most likely have to return to your home country as soon as transportation is available.
In some cases, people who already have green cards will be checked for inadmissibility when they return to the U.S. after travel to another country. This happens when the person departs the United States for more than 180 days.
For example, the returning traveler might have committed a crime that is a ground of inadmissibility, developed tuberculosis, or begun receiving public assistance since the date of receiving the green card. In such situations, however, you might be "paroled" into the United States for purposes of arguing the finding.
The prospect of being found inadmissible after foreign travel is a good reason for green card holders to apply for U.S. citizenship as soon as possible. For help, see Becoming a U.S. Citizen: A Guide to the Law, Exam, and Interview, by Ilona Bray (Nolo).
You might be able to get around your inadmissibility problem. For example, if your illness can be cured, or the doctor diagnosed you wrong in the first place, getting follow-up treatment and/or a letter from another doctor could help you get a green card. Or perhaps your fingerprints got confused with someone else's, or the U.S. government made some other mistake in your case. There too, you'd need to present documents proving the mistake.
Even if you are inadmissible, you might be able to apply for a waiver. That means you ask U.S. immigration authorities to overlook the problem and admit you anyway. Waivers aren't easy to obtain however, and usually depend on having U.S. citizen or permanent resident relatives who would experience extreme hardship if you were denied the visa or green card or U.S. entry.
A number of technical factors control whether you are found inadmissible, and if so, whether you can overcome that finding. You might ultimately need to hire a good immigration lawyer, particularly if you need to analyze the implications of a criminal conviction or apply for a waiver.
Applying for a waiver is much more complicated than merely filling out a form. You will need to collect documents, write affidavits, and otherwise present a convincing argument for why you should be granted U.S. entry.