If people are concerned with imported labor undecutting or putting downward pressure on salaries, I'd suggest taxing imported labor so as to make it no cheaper than the locally produced labor pool. Then we'd get companies hiring imported labor when they actually could not find a local candidate.<p>Tax it at the median recorded for the locale where the sponsoree is hired. Tax so that there is no cost advantage in seeking labor cost arbitrage.<p>You could simply tax the difference. If the median is 150, and someone is hired for 100, tax is 50. If they are hired at 130, tax is 20, etc.