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.
And the sad thing is we know what a real compromise bill looks like:
https://en.m.wikipedia.org/wiki/Border_Security,_Economic_Opportunity,_and_Immigration_Modernization_Act_of_2013If Senators and Representatives on both sides would just shut up and pass that bill, this crisis would be over.