Quick Clarification:
All Illegal Aliens are Criminals.
They by their act of entering our Nation illegally violated US Immigration Laws which is a Crime.
Many of them Voted Illegally in our US Elections which also is a Crime.
Many of them are engaging in Financial Fraud which is also a Crime.

That said, IMO...
ICE is rounding up VIOLENT CRIMINALS as a First Phase that by their very evil nature pose immediate danger and safety hazard to the American Public.

I reckon that the Second Phase will be rounding up Financial Criminals.
Perhaps the Third Phase will be rounding up those who Illegally Voted,
or maybe these 2 Phases simultaneously.

Then as a Final Phase, NESARA-GESARA-TRUMPSARA will incentivize those who simply came here illegally for work opportunity to GO HOME, self-deport in a mass exodus, as they will not receive any benefit except if they return to their home country.

Those Phases completed would probably leave few if any Illegals to detain & deport, hopefull