If he wants it to go through he has to cut a deal. It's a win/win so I'm not sure that the holdup is. Other than progressives getting their panties in a bunch.
His plan seems to be to force rail traffic on exports from Mexico to the US to be blocked until Mexico does something about stopping the migrant flow for him. I don't know what he thinks that's going to do for our economy or for getting the R's to fund Ukraine