What are you talking about? All 49 Dem Senators (even Manchin) have signed onto SB 3036, cosponsored by Republicans. Beto is introducing a House Bill today.
If you are referring to comprehensive immigration reform, Democrats have tried working with Republicans only to face a flip-flop in the end. They can't unilaterally do anything until after the midterms at the earliest.
The Administration is coming at this from stupid...there is no reasoning with these people. The only way a zero-tolerance illegal immigration policy will work (and long-term it's the RIGHT thing to do!) is by INCREASING legal immigration (guest worker programs, temp visas based on skills etc., one-time DACA, perhaps even a path to permanent residency for some illegals.) But Trump wants to cut legal immigration 75% and fully fund a massive infrastructure project up front (almost as dumb as forcing the post office to fully fund retirement up front!)
If we really need a quick fix to curb illegal immigration and asylum seekers, I propose we fund a massive ad campaign in Mexico, Guatemala, and El Salvador and other hot spots. TV, radio, print, billboards and bus stops, etc. Show the images of people falling off trains and getting dismembered. Show migrants who were cooked alive inside a tractor trailer. Show young girls getting sold as sex slaves , show people getting kidnapped for ransom, etc. etc. Then show the people who actually make it across the border getting thrown in detention. Caption: "It isn't worth your life".
Unless and until we can do that, we won't stem the tide.