IMMIGRATION is the quintessential supply-side policy. It expands the labour force, encourages investment and provides taxpayers to supportAmerica’s growing ranks of the grey-haired. Sadly, Barack Obama’s immigration order will have few such benefits, because it is aimed largely at illegal immigrants who arrived years ago while doing precious little to increase the flow of newcomers.

The reform that passed the Senate last year (but was never taken up by the House of Representatives), besides legalising millions of illegal immigrants, would have created new entry routes for foreign workers, especially those with skills, experience and education. The Congressional Budget Office reckoned it would boost the population in a decade’s time by10m, the number of workers by6m, and the level of GDP by 3.3%.

By contrast, Mr Obama’s Council of Economic Advisers reckons his order will boost GDP in the next decade by between 0.4% and 0.9%, mostly because of provisions unrelated to illegal immigration. These give foreign entrepreneurs more ways to get into America, allow the spouses of skilled visa-holders to work, and let foreign-born science graduates spend more time in America doing their training.

In theory, the economy should benefit as illegal immigrants, no longer fearing they will be deported, switch to jobs better suited to their skills. But that advantage is likely to be small: a study by Silvia Helena Barcellos, now at the University of Southern California, found that Mexican high-school dropouts who qualified for the 1986 amnesty earned only 2-3% more than those who did not qualify, and that there was little difference in where they worked or the types of jobs they had, though their better-educated counterparts got better jobs.(Economist)

翻译：

移民政策事关国家供给。它能扩充劳动力，鼓励投资，提供纳税人去赡养美国日益增多的老龄人口。但遗憾的是，巴拉克·奥巴马的移民很难带来这些好处。因为这些条例仅主要针对多年前偷渡到美国的非法移民们，但对于增强新移民的流动性，帮助甚少。

参议院去年一致通过了移民改革政策(但却从没有征得众议院的同意)。除了让数百万非法移民合法化，将会为外籍工人尤其是那些有技能、经验以及受过高等教育的人，创造新的移民途径。国会预算办公室估算，未来十年内，新的政策将会促使总人口达到10亿规模，劳动力人口达到6亿，国内生产总值增速达3.3%

相反的，经济顾问委员会估算，未来十年内，主要因为非法移民的无关规定，奥巴马的新条例仅会促使美国国内生产总值增长0.4%-0.9%。这给了外资企业更多进入美国市场的机会，并且允许持有技术签证的配偶们在美国工作，让外籍理工科毕业生在美国停留更长时间完成科研、训练。

理论上，非法移民处境的改善能够国家经济收益，这些非法移民们可以切换到能发挥他们技能的工作岗位上，并且不再害怕被驱逐出境。但是这个益处看上去微不足道。南加州大学西尔维亚·海伦娜·巴塞罗斯通过研究发现，1986年大赦的那些墨西哥高中辍学者的收入仅仅只比那些没有得到特赦资格的人多2-3%，虽然受过良好教育的同行有更好的工作，但是他们的工作种类却没有太大的差别。