There is silence because neither party wants to stop illegal immigration.
Dems and GOP'ers don't want to stop it, Business, both big and small don't want to stop it. Unions don't want to stop it, and Churches don't want to stop it.
There is no organized constituency opposed to Illegal Immigration, while there are several who are for it.
Who are the majority of the "migrants" in the world today? Hispanics, Africans??? This country has only a given capacity (and an economic need) to absorb newcomers. If we greatly limited the number of Mexicans crossing the border, we would greatly raise the legal immigration limits and accept far more Africans. (Of necessity...Big-Ag needs chicken-pluckers.) Do you suppose that those who lobby for "unrestricted" illegal Hispanic immigration are simply trying to keep the really darkies out???