Ineligibility and Waivers with crime does present a problem. If your Thai wife or your Thai fiancée has been denied a visa then a criminal record might be why this has been denied. Below is a brief overview of what types of crimes are looked and also what your options would be for an appeal. Note that you would have to take proper legal advice from an immigration lawyer in Thailand for assistance as well as guidance.
Ineligibility and Waivers with Crime
Should your Thai wife or fiancée not have a criminal record she might say something at the visa interview which could get the visa denied. The law states that the visa can be denied where the person has been convicted of, or who admits having committed, or who admits committing acts which constitute a crime. If your Thai wife decided to admit to a crime then the visa will clearly be denied. These relate to drugs as well.
There are exceptions but you would have to take legal advice in this regards as it only covers one singular crime when she was under the age of 18 and that she was released at least more than 5 years before the visa application. These are for crimes that did not get a prison sentence for longer than 6 months. In other words these are for petty crimes when she was under the age of 18. Again take proper legal advice as this is only a very brief overview of the many issues and does not constitute legal advice.
Purely political crimes are not a real issue with these applications and those convicted of multi crimes certainly will be denied a visa. These will show on the police criminal record which she will have to obtain from special branch police in Thailand for the visa process in any event. Drug trafficking would also not generally allow you access to the US. Prostitution will also be a major issue.
If the consular officer believes that you are going to export from the United States of goods, technology, or sensitive information then a visa will also be denied. If they suspect that your wife or fiancée might be involved in any terrorist activity then the visa will also be denied.
What is the most common issues in Thailand?
When it comes to ineligibility and waivers with crime, the more common issue is that your Thai fiancée or wife might have been deported from the US for overstaying her previous visa. She might also have been convicted of a crime in the US during that time such as solicitation.
The next common problem might be that your Thai fiancée or wife might not have all the paperwork in order and this is also extremely common. The vaccination certificates are not correct or that there is missing paperwork with the medical checkup.
Lastly that you and your wife or fiancée are in a sham marriage or relationship. This would normally crop up during the visa interview process.
Having a criminal record is not going to be helpful when applying for the US visa from Thailand. If the visa is denied they will give you a reason for the visa denial and you can base your appeal on this legal issue. It is however very difficult to do a visa appeal in Thailand without proper thought and additional paperwork. Note also that if you apply for a K2 visa or K4 visa for children than child delinquency or their criminal activity might also prove to be an issue.
Take proper legal advice when it comes to ineligibility and waivers with crime.