The combination of increasingly costly and risky trips and the near certainty of getting into the United States created a decision-making context in which it still made economic sense to migrate but not to return home to face the high costs and risks of subsequent entry attempts. In response to the changed incentives, the probability of returning from a first trip fell sharply after the 1980s, going from a high of 0.48 in 1980 to zero in 2010, though with significant year-to-year variation connected to fluctuating social and economic conditions in Mexico and the United States. According to our instrumental variable estimates, if U.S. border enforcement were the only causal factor affecting the likelihood of return from a first trip, it would have fallen from a peak of 0.47 in 1981 to a low of 0.17 in 2010, a drop of roughly two-thirds in a little less than three decades.