失去移民，美国经济将会怎样

    随着2014年中期选举越来越近，民主党将把移民制度改革问题当做突破口，以此向存在弱点的共和党人施压，迫使共和党人要么激怒选民、支持移民制度改革，要么失去这个关键群体的人心。

    涉及移民有关的政治问题很复杂，经济问题也是如此。移民到底是不是降低了美国低技能劳动者的工资水平？研究者们对这个问题莫衷一是。但就其他问题而言，比如移民是否促进了整体经济增长，数据一清二楚。移民绝对是经济增长的动力所在。

    要凸显这一点，途径之一是用过去30年美国的经济增长速度和法国、英国、日本等富裕国家进行比较。人们经常挂在嘴边的一个事实是，差不多80年的经济数据显示，美国的增长速度一直比其他国家快，原因是美国更热衷于坚持经典的资本主义原则。大家可以看看下面这幅图，显示的是从1982年到2012年的名义GDP年度增长率（其中蓝色曲线为美国，橙色为法国，红色为英国，绿色为日本）：

    As the 2014 midterm elections draw nearer, the issue of immigration reform will be used as a wedge to pressure vulnerable Republicans into either angering their base and supporting reform, or alienating key demographics.

    The politics of immigration are complicated, as are the economics. Researchers are split over whether immigration brings down the wages of low-skilled workers in the U.S. But with respect to other questions, like whether immigration promotes overall economic growth, the data is clear. It overwhelmingly does.

    One way to highlight this is to compare economic growth over the past 30 years in the U.S. to other wealthy countries like France, the U.K., and Japan. A stylized fact often thrown about is that the United States, over the 80 or so years in which we've measured this sort of thing, has consistently grown faster than other countries due to its more enthusiastic adherence to classic capitalistic principals. Check out the graph below, which shows nominal yearly GDP growth from 1982 to 2012:

    如图所示，美国的表现一直好于同类富裕国家。在这30年中，美国的平均名义GDP增长率为5.4%，法国为1.8%，英国和日本分别为2.4%和1.9%。

    但人们经常忽略这样一个事实，那就是和同类工业化国家相比，美国的人口增长率一直较高。现在，让我们再看一下这30年间的经济增速，衡量标准是人均GDP：

    As you can see, the U.S. consistently beats out its wealthy peers. Over this period, nominal GDP growth in the U.S. has averaged 5.4%, compared with 1.8% in France, 2.4% in the U.K., and 1.9% in Japan.

    But one fact that often gets overlooked is that the U.S. population has been and continues to grow at a faster rate than its industrialized peers. Take a look now at GDP growth over that same period, this time on a per capita basis: