President Trump's immigration crackdown is causing one of the sharpest slowdowns in U.S. population growth in decades. Economists are beginning to tally the effects, with some warning that the damage will stick around. Why it matters: The policy-driven immigration reversal underway has few modern parallels. The immediate result is evident in monthly employment figures, with the economy cranking out fewer jobs. But over time, fewer immigrants could be a productivity drag lasting well into the s