The need for ICE has to do with jurisdiction. Immigration and customs (ivory and stuff like that) are federal matters. A lot of federal stuff gets handled by fe

The need for ICE has to do with jurisdiction. Immigration and customs (ivory and stuff like that) are federal matters. A lot of federal stuff gets handled by federal police agencies, like the DEA and the ATF. The Secret Services investigates and disrupts counterfeiting and money laundering. The IRS has a small number of armed officers that perform arrests for very specific crimes. The reason for this separation has to do with consistency and scope: legality of immigration, and illegality of counterfeiting, should be consistently the same from state to state. Cases involving these issues could happen in any state and are likely to involve more than one state at a time, whereas most police work usually involves only a small area. They also are not areas where the states have authority to set policy, so it could create difficult situation for police if there were a disagreement between their state and the federal government over an issue like income tax. These factors together seem to explain why we have so many federal police forces. How would things be better if local police had authority to detain and deport people, or to investigate customs matters?