Agricultural states generally like immigration. If you go to North Carolina you will see Spanish translations on everything, hear Spanish on the radio etc. For quite some time NC was where people went to get fake ID, until recently.National borders are not one of these. One state like Cali with no concern about the border will just enable people to flood other states. Those states may have to create their own state border controls hampering commence over state lines.
The US always had a border patrol. We've always had illegals. We've almost always had mafia. We've had Irish pouring in, Germans, Greek, Iranians, Russians, Italians, Cubans, Puerto Ricans, Chinese and just about everybody coming in here and stealing our jobs and marrying our women. After two centuries of it you'd think we'd learn.
2 things really matter. 1. The ethnicity of our population is changing rapidly. 2. Television is the new melting pot.