Caren, I understand where you're coming from for the purposes of your article here.
But there are good arguments in favor of the federal government devolving power over immigration to the states. With the federal monopoly of the issue NOTHING is likely to move forward. At a more local level states can decide what best suits their interests. Sure many will try new walls but others would take a different course and possibly enable talent to enter the country. Many northeastern states understand that could benefit from imports of people.
Sanctuary cities have already wrested power away from the federal government on the issue largely to their benefit.
Many thanks. Best to you.