I’m not a lawyer, but I really don’t see how this is legal, unless executed in a very particular way. I really only think this is legal if a state’s governor allows their NG troops to work with ICE under Title 32 within that state alone. Once a state’s Guard gets federalized, they are working under Title 10. The important difference is that Title 32 grants governors the ability to use their NG for law enforcement, but Title 10 means that they fall under DoD policy, and therefore subject to Posse Comitatus and unable to engage in law enforcement unless legislation is passed.

With that said, the only way I could see this being used is within states with friendly governors (so red states) who mobilize their NG and offer DHS their personnel as aid. But then those personnel could only be used in their state. So, if Indiana mobilized their Guard on Title 32 orders and aided ICE, then they could only operate within Indiana unless invited into another state. If ICE wants to do a raid with Guard personnel in Chicago, then they are SOL because then that would be an interstate invasion.

What this could do is allow ICE personnel to focus on Democratic states while Republicans use their NG to do the majority of ICE’s dirty work. In other words, a bunch of ICE people will come to blue states to do the rounding up, while NG will do the rounding up in red states.