The simple problem here is that Democrats want to preserve the status quo on immigration. Cyclical amnesty and the key to that is never actually getting the enforcement or blocking it until a new illegal population is built up so you can cry foul and claim you cannot enforce until the system is "reformed" and those here now are legalized. Rinse, Wash, Repeat!
Never before was their such a divide on the immigration issue with Hillary going so far as to pledge to end all deportations (effectively declaring open borders) while Trump ran on a wall. If the Democrats want to hang their heads on the policy of open borders and refuse to compromise at all on enforcement, then they better hope they can pull off a sunbelt strategy, because there is no way they will regain the rust belt with that approach.
Even Obama paid lip service to the standard lie of "enforcement" in comprehensive reform, deported millions of illegals and called for a crack down on employers who hire illegals.
Our nation desperately needs an honest conversation on immigration. And that's not something we have gotten from either party in a long time.
We need immigration and immigrant labor. Or we need to reform our entire economy and society. No one wants to admit that.
Besides being used as a political flail, our de facto current policy is to create an abused underclass of workers who are not protected by labor or other laws. That has to stop. It's bad for working Americans and it's evil.
Anyone who works in this country needs to have the full protection of the law. And the pretending walls and securing the border will have any effect on illegal immigration needs to stop. We need to admit we're going to have a lot of immigration and help (not force) immigrants assimilate. And we need to lose the rabid xenophobia.