I often get calls from people who are not U.S. citizens, and who have pled guilty or no contest to a criminal charge. Unfortunately, for many of these people, it is too late to do anything about the immigration consequences of the criminal conviction. In the State of Florida, there are deadlines for going back and challenging a previous criminal conviction. So, for example, if you pled guilty four years ago to a domestic battery, and now you want to go visit your family in Germany, upon reentry to the United States, you would likely be placed in deportation proceedings, because a domestic violence conviction makes you inadmissible and deportable.
Now, you may tell me that your criminal lawyer did not properly advise you that a domestic battery conviction, or even a withhold of adjudication, would result in you being inadmissible and deportable. If that prior conviction was within the last two years, you may be able to go back and reopen your criminal case. However, if it is more than two years old, the law in the State of Florida would not allow you to challenge the prior conviction on the grounds that you were not properly advised of the immigration consequences.
Criminal convictions have serious and long lasting immigration consequences. Whether you are here without any lawful status, or whether you have had a greencard for decades, even a very old and minor criminal conviction can make you deportable. If you have any (and I mean any) criminal charge at any time in the past, it is extremely important to consult an immigration attorney before you leave the country or have any contact with any immigration official (i.e. USCIS, ICE, CBP).