A good The New Yorker introduction to very recent (October 2018) policy issue of naturalization of permanent residents (green card holders).
Hanson, Liu and McIntosh on immigration to the US by low-skilled young workers. Abstract: From the 1970s to the early 2000s, the United States experienced an epochal wave of low-skilled immigration. Since the Great Recession, however, U.S. borders have become a far less active place when it comes to the net arrival of foreign workers. The number of undocumented immigrants has declined in absolute terms, while the overall population of low-skilled, foreign-born workers has remained stable. We examine how the scale and composition of low-skilled immigration in the United States have evolved over time, and how relative income growth and demographic shifts in the Western Hemisphere have contributed to the recent immigration slowdown. Because major source countries for U.S. immigration are now seeing and will continue to see weak growth of the labor supply relative to the United States, future immigration rates of young, low-skilled workers appear unlikely to rebound, whether or not U.S. immigration policies tighten further.
Hanson and McIntosh comparing Rio Grande and Mediterranean flows into the future.
The National Review’s Reiham Salam on politics of immigration.