Immigration law uses its own definitions
A charge dismissed in criminal court can still matter. A plea that avoided jail can still count as a conviction for immigration purposes. Certain offences carry consequences well out of proportion to their criminal sentence. The two systems do not line up, and assuming they do is the most common and most expensive mistake.
Where it shows up
At naturalization, where good moral character is assessed. At adjustment of status and at consular processing, through the inadmissibility grounds. At the border on re-entry. And in removal proceedings, where certain categories limit the relief available.
Get the record before you file anything
Obtain the certified disposition for every arrest, including ones that went nowhere. What the record actually says frequently differs from what someone remembers being told.
Waivers and post-conviction options exist
Some grounds can be waived. In some cases a criminal matter can be revisited where the immigration consequence was not properly advised. Both are time sensitive, and both need assessment before a form is submitted.
