Bangladesh, Sept. 1 -- A growing populist argument calls for taxing remittances, penalizing employers and using forfeited assets to finance deportation and support American workers. But such a policy would face major constitutional, legal and economic obstacles.

The debate over illegal immigration in the United States has increasingly moved beyond questions of border security and deportation. A more sweeping proposal is now entering the political conversation: if the government undertakes large-scale deportations, should it also seek to recover money and property connected to illegal immigration?

Supporters of the idea argue that deportation alone would not address what they regard as the economic consequences of unauthorized migration....