There are several discernible groups within the movement, with separate interests, origins, and aims. The modern immigration reduction movement has many antecedents. Some cite the nativist United States American Party (often called the Know Nothing movement) of the 19th century and the Immigration Restriction League of the early 20th century as antecedents.
Organized labor and parts of the political left have also had an ongoing debate over immigration levels into the U.S. going back to the 19th century. The National Labor Union (1866-1874) campaigned for immigration restrictions as well as the eight-hour workday, as did the American Federation of Labor under the leadership of Samuel Gompers. The AFL-CIO did not reverse its position on immigration restrictions until 1999. The early United States Socialist Party was split over the issue, with some Socialist leaders including Jack London and Congressman Victor Berger supporting immigration restrictions; the party as a whole never had consensus, and only went on record in opposition to the importation of strikebreakers.
A separate issue with some overlap was concern over overpopulation. The leading early influence on that issue was Paul R. Ehrlich, who both founded Zero Population Growth and published The Population Bomb in 1968. The popular book foretold alarming disasters that would inevitably occur in the next decades. Though some of his predictions did not come to pass, many believe his main points are valid, and they succeeded in inspiring a movement. Environmentalists including David R. Brower and David Foreman took the threat seriously. The Zero Population Growth organization did not involve itself, for the most part, in U.S. immigration policy, and a subset of the overpopulation movement grew which believed that immigration needed to be reduced, arguing that immigration was driving most U.S. population growth. These activists founded organizations separate from ZPG which would specifically address immigration issues. Among the important early organizations was Negative Population Growth, founded in 1972 by Donald Mann.
The leading inspiration for the modern movement is John Tanton, a self-described progressive and critic of neoclassical economics.
Tanton founded the Federation for American Immigration Reform (FAIR) in 1979, the largest and best funded organization in the movement. Three years later, Tanton formed US, Inc. as an incubator and funding source to help form other organizations. According to public tax records, US, Inc, FAIR, and other Tanton organizations have received large donations from the Pioneer Fund and from the foundations controlled by Richard Mellon Scaife. Tanton created US English (an English-only advocacy group), the Center for Immigration Studies (CIS), ProEnglish (another English-only advocacy group), and The Social Contract Press. US, Inc and FAIR have provided funding and logistical support to other organizations, including American Immigration Control Foundation (AICF), California Coalition for Immigration Reform (CCIR), Californians for Population Stabilization (CAPS), and the recent Protect Arizona Now (PAN) initiative, Proposition 200. FAIR points out that there is a relationship between lax immigration policies and terrorism such as the 9/11 attack, and it asserts there is no connection between itself and eugenics.
The movement seemed to be triumphant in 1994 when California voters passed Proposition 187, an initiative which limited benefits to illegal aliens that had been authored and promoted by CCIR. However it turned out to be a Pyrrhic victory. One federal judge enjoined implementation of parts of the law as unconstitutional, and Democratic governor Gray Davis refused to pursue an appeal of the lower court decision, abandoning Proposition 187. Residual resentment over the racially divisive campaigns on both sides of the issue made immigration a topic that politicians largely avoided dealing with. A notable exception has been Tom Tancredo, who was elected to Congress from Littleton, Colorado in 1994. Together with Patrick Buchanan and the Tanton network, Tancredo has emerged as the most conspicuous voice advocating immigration reform in Congress.
The immigration reduction movement was partly rejuvenated by The Alliance for Stabilizing America's Population coalition. In 1997 members from a range of immigration reduction and environmental organizations met to rededicate themselves to the effort of population stabilization. Organized by Population-Environment Balance, it included such diverse groups as:
Another effort was the coalition formed under the name U.S. Sustainable Population Policy Project (USS3P) in 1996 by Douglas La Follette and David Pimentel. The USS3P membership contained many immigration reductionists of the time. In 1999 it sought cosponsors for a major national conference on immigration. A number of major individuals and minor organizations joined as co-sponsors, but no large national groups joined and it folded in 2000 without holding the intended conference.
The Internet offered new opportunities for communication by immigration reductionists, as it has with countless other movements. Peter Brimelow founded his VDARE writers collective in 1999. The year 1999 also saw the founding by Craig Nelson of ProjectUSA in New York City, which used billboards to advertise Census Bureau and other statistics about immigration in a campaign dubbed "Billboard Democracy," and publishes an ezine in which the term "Minuteman" was first used (2002) in connection with civilian border patrols. The NumbersUSA group founded by Roy Beck set up automated system for website visitors to send advocacy faxes to their legislators on immigration topics. Numerous websites, email lists, weblogs, and other resources furthered the effort.
The electoral success of Arizona's Proposition 200, PAN, indicates the support for immigration reductionism among voters. The PAN initiative qualified for the ballot following the expenditure by FAIR of hundreds of thousands of dollars for signature gathering, plus comparable sums for campaigning with some additional amounts raised locally. The initiative was adopted by the public by a significant margin and is likely to inspire similar efforts in other states. The success of Proposition 200 in Arizona was followed in April 2005 by the Minuteman Project, in which volunteers came to Arizona to help patrol the border, although this project did not have the support of the United States Border Patrol and generated some controversy. The organizers of the Minuteman Project have announced plans for similar projects in other states including Texas, California, and Michigan.
Reasons for favoring immigration reduction given by supporters include:
calling for a "non-piercable" cap of 100,000 persons annually, which would be a 95% cut from current levels. Carrying Capacity Network (CCN), another small reductionist group closely related to PEB, shares that goal while repeating that it is not opposed to immigration.There are also some who support a moratorium on immigration. The Diversity Alliance for a Sustainable America claims that 43% of Californians polled said that a 3-year moratorium on immigration would be beneficial to the state (compared to 40% who said it would be unbeneficial).
The America First Party calls for a ten-year moratorium, with only spouses and children of citizens allowed in.
Other advocates for moratoriums include the Reform Party
and 2004 Constitution Party presidential candidate Michael Peroutka
Robert Locke surpasses them by calling for a negative immigration rate. He has defined this as restricting immigration to the U.S. to what he calls the "normal" (i.e., pre-1965) average flow of immigrants throughout U.S. history, combined with the deportation of all illegal immigrants. 
The Carrying Capacity Network (CCN) and Population-Environment Balance, two groups that both operate out of the same Washington, D.C. address, issue frequent statements that advocating for the numbers recommended by the Jordan Commission, 700,000 annually, is "counter-productive". In a National Alert the CCN warned that organizations supporting numbers higher than 300,000 undercut the movement, and they specifically criticize the Federation for American Immigration Reform and NumbersUSA. 
Some groups not connected to the immigration reduction movement nonetheless support a reduction to legal immigration levels of around 500,000 to 600,000. In their 1997 book, Misplaced Blame, Alan Durning and Christopher Crowther of Northwest Environment Watch write that illegal immigration gets too much attention, and identify five main sources of population growth, including lack of access to family planning as well as a misguided legal immigration policy, and subsidies to domestic migration. They readily admit that immigation should be reduced by an unspecified amount, but they also show concern for the rights of existing residents.
The AFL-CIO and some mainstream environmentalist groups used to be on record favoring lower immigration numbers, although most have quietly dropped this position in recent years.
Many immigration restrictionists question the 1898 Supreme Court ruling U.S. v. Wong Kim Ark, which held that individuals born on U.S. soil to non-citizen parents are U.S. citizens and guaranteed all the rights thereof. They feel that citizenship should be denied to the children of immigrants without valid immigration status. Thus they have sought to end birthright citizenship, through a constitutional amendment or a congressional act.
Denial of public benefits to undocumented individuals is believed to remove the incentives and rewards for illegal immigrants. The 1994 California Proposition 187 and the 2004 Arizona Proposition 200 Protect Arizona Now were written to require proof of legal status in order to receive non-mandated benefits.
The Federation for American Immigration Reform has spoken out in 2004 against the views of another reductionist leader, Virginia Abernethy, calling her views "repulsive separatist views," and called on her to resign from the advisory board of Protect Arizona Now in Arizona. The two groups closely associated with Abernethy, Population-Environment Balance and the Carrying Capacity Network, have been issuing statements since 2003 accusing FAIR and NumbersUSA of being "reform lite" and "undermining real immigration reform." PEB and CCN are also critical of FAIR for FAIR's support of a national ID card, which PEB and CCN oppose. The Protect Arizona Now movement split, with two rival state-level organizations, one supported by FAIR, the other supported by PEB and CCN, working to support the passage of the ballot initiative.
Selected immigration reduction links: