Trump is right that undocumented immigrants with little education push down the wages of some other workers, but the losers are largely prior immigrants and American high school dropouts. He’s also right that illegal immigrants cost state and local governments some money. But Trump also says that what matters on immigration policy is whether it improves the well-being of the American people. Looking at the effects of immigration over multiple generations, and across all types of workers and employers, the study overwhelmingly shows that it does. Sorry, Donald, I tried.