Just a thought, but is their real concern the "workers", or just how many dues paying members they have, and therefore influence they can peddle?
I used to work in the HQ of the US Customs & Border Patrol. Everyone knew that the US could seal the borders in a heart beat if there were any political will to do so from the top.
There was none. And there is not much now.
The basic story on this stuff is that the leadership of both the republican and democratic parties would sell the US into Mexican slavery in a heart beat if they could just get away with it. The top republicans are looking for cheap labor and the top democrats are looking for cheap votes.
The rank and file of both parties just despise the whole mess.
So we'll get some crappy bs that just kicks the can down the road and will make for increadible problems for the USA in a couple decades. We'll get the political equivalent of the 3/5ths compromise.
Heaven help the USA.
I thought history had shown that it was neither, but more along the line of how much can the leadership steal.