Before a Judge will accept any form of negotiated plea on a DUI case, he or she will advise a defendant that any criminal conviction may lead to immigration consequences if the defendant is not a citizen of the United States. Some Judges will state that a conviction will lead to deportation, denial of naturalization or citizenship or denial of entry into the country.
I routinely advise clients to seek independent legal counsel from an immigration attorney if they have immigration concerns. However, I have been advised by immigration attorneys that a standard first time DUI would not lead to any serious immigration consequences such as deportation. Problems arise if there is a county jail sentence to be served. The immigration authorities may pick up a non-citizen defendant from county jail and begin deportation proceedings. This typically happens for a defendant on a second or third time DUI. A felony DUI would certainly lead to denial of citizenship and deportation. Even on a first offense, a person may not complete a citizenship application until they have completed any period of probation.
I have also been informed by immigration attorneys that in determining the relevance of a criminal conviction, the INS will look at the maximum penalty for the offense. If the maximum penalty is under six months county jail (including a reckless driving conviction), they will ignore it. If the maximum penalty is less than twelve months but six months or more (including a first time misdemeanor DUI), they may take it into account on a discretionary basis. If the maximum penalty is twelve months or more (including a second or third DUI), they would normally deny citizenship.