Someone should ask the Post's editorial board that question. The Post's editorial on the new immigration bill comments on the "annual flow of 400,000 to 600,000 low-skilled workers needed to satisfy the demand for labor." Wages in the jobs typically filled by these immigrants (custodians, restaurant workers, nannies) have been stagnant or declining over the last quarter century. To those who believe in markets (which in other circumstances includes the Post's editorial board), this implies that a large flow of immigrants is not needed to fill the demand for labor. Of course, an increased supply of labor will help keep down wages in this sector of the labor market.
--Dean Baker
