For many years Democrats controlled Congress and the presidency... and did not address the problem either.
This is because the corporate interests who lobby and fund both parties want to be sure nothing is done to tighten hiring rules that would make corporations, owners, and farmers responsible for their knowingly hiring illegal immigrants --- these employers like cheap labor. And both parties have winked at this problem for a long time.
But Democrats aren't making this their core issue, Republicans are.
Immigration is the most important problem for all of you Republicans in every poll, why should Democrats worry about what the Republican voters want.
You can blame corporate interests and what not, the fact is that this is about money and for Republicans, money comes first and life/liberty/family second. Corporate interests dont want a trade war either, that didnt stop Trump from starting it but on this issue which doesn't impact the big corporations much, he doesn't want to do anything?
Makes no sense.