"Four major principles underlie current U.S. policy on permanent immigration: the reunification of families, the admission of immigrants with needed skills, the protection of refugees, and the diversity of admissions by country of origin. These principles are embodied in the Immigration and Nationality Act (INA). The INA specifies a complex set of numerical limits and preference categories that give priorities for permanent immigration reflecting these principles. Legal permanent residents (LPRs) refer to foreign nationals who live permanently in the United States. During FY2010, a total of 1.0 million aliens became LPRs in the United States. Of this total, 66.3% entered on the basis of family ties. Immediate relatives of U.S. citizens made up the single largest group of immigrants--476,414--in FY2010. Other major categories in FY2010 were employment-based LPRs (including spouses and children) and refugees/asylees adjusting to LPR status--14.2% and 13.1%, respectively. About 13.3% all LPRs come from Mexico, which sent 139,120 LPRs in FY2010. Substantial efforts to reform legal immigration have failed in the recent past, prompting some to characterize the issue as a 'zero-sum game' or a 'third rail.' The challenge inherent in reforming legal immigration is balancing employers' hopes to increase the supply of legally present foreign workers, families' longing to re-unite and live together, and a widely shared wish among the various stakeholders to improve the policies governing legal immigration into the country. Whether the Congress will act to alter immigration policies--either in the form of comprehensive immigration reform or in the form of incremental revisions aimed at strategic changes--is at the crux of the debate. Addressing these contentious policy reforms against the backdrop of high unemployment sharpens the social and business cleavages and may narrow the range of options."
CRS Report for Congress, RL32235