I think that the individual cities and states should not be policing immigration that is the job of ICE. NYC did/didn't do the right thing.
If ICE wants to deport anyone because they are here illegally then ICE should take responsibility for deporting them. Cities like NY have enough problems with crime for them to be focusing on immigration and deportation. If ICE want any city/state to be enforcing immigration the should have a separate department to do that with separate holding areas and leave the holding cells in the precincts and jails for true criminals. That said if someone is arrested for a crime and said person is not with legal status, then they should go through the legal process like any citizen have them serve whatever sentences handed out.
If said person appears on a provided list by ICE of illegals then that city/state should contact ICE and make them aware of such person, if ICE want such person deported then ICE should take custody of that person and execute the deportation themselves and not burden city/state with it, there are more pressing issues to deal with.
This is how i think the process should go...
ICE provide list to cities/states.......
Arrested names verify on list......
Prosecute arrested and justice handed down.....
ICE notified of arrest......
Deportation?
ICE take custody........
Execute deportation....
Thank You