Learn more about the root causes of immigration~ read below

(we didn't write this, it's all taken from afsc.org/immigrant-rights/learn/roots.htm)

The Roots of Migration
The decision to leave one’s home for another country is never a simple one. As with any major life choice, it is usually shaped by many different factors. In general, there are three major reasons why people leave their home countries:
To flee violence, war, or political persecution.
To seek economic security or survival.
To join with family members.
Very often, a combination of two or all three of these factors is present.
Violence
A relatively small number of people are officially admitted to the United States as refugees or asylees . A much larger number of people, however, have come here fleeing persecution, violence, or warfare. Others have fled the severe economic dislocation that always accompanies war. As violent conflicts and outright war increase around the world, millions more people will be forced out of their homes.
Refugees most often flee to nearby countries or to countries with strong ties with their home country. Only a small percentage comes to the United States. According to the United Nations, at the end of 2000, the worldwide population of refugees and other displaced people was dispersed among Asia (38.8 percent), Africa (27.9 percent), Europe (25.6 percent), North America (4.8 percent), and Latin America and the Caribbean (2.6 percent).
Economics
Economic motives are the strongest force promoting immigration. Often, however, the economic roots of immigration are poorly understood. Politicians and media commentators paint a picture of immigrants coming from poor countries to rich countries like the United States in order to take advantage of public benefits or higher wage levels. The reality is considerably more complicated.
Many immigrants are essentially economic refugees. In the era of globalization, governments around the world have faced a great deal of pressure to reduce public investment in infrastructure, services, credit, and job creation. Public subsidies for food and agriculture have also been slashed or eliminated, and small-scale farmers have been forced to compete with huge international agribusiness firms.
While these policies have a negative effect on all countries, their impact on developing countries has often been devastating. Without access to credit or markets, small farmers cannot survive on the land. Rural communities are depopulated as their inhabitants migrate to cities or across national borders.
Small and medium-sized business and industry are affected in similar ways, and their workers also join the migrant stream. As government around the world is “downsized” and public support for health and education is eroded, even the middle classes are affected by economic displacement. “There were no jobs, we had to leave” is a story told by millions upon millions of immigrants.
Globalization is also connected with immigration in other, more complicated ways. Some researchers have argued that international investment flows create a sort of economic bridge between developing countries and advanced industrial countries. Foreign investment, especially in the developing world, is often defended as a strategy for job creation. In reality, however, people who leave developing countries usually migrate to the rich countries that account for the most foreign investment in their economies. This is one reason why most people leaving Africa migrate to France or the United Kingdom, while people from Mexico are more likely to migrate to the United States. In recent years, as investment flows have become more diverse, so have migrant destinations.
These economic bridges reflect even older economic and political relationships, forged in the era of colonialism. Under the colonial system, European nations and, later, the United States ruled over most of the developing world, carving it up among themselves into “spheres of influence.” Today, all but a small handful of developing countries have their own governments. The old relationships, however, persist in a new form, creating bridges — economic, political, and cultural — that structure international migration flows.
International economic policies favored by global elites have also structured a steadily increasing flow of the world’s wealth — away from the developing world and toward the advanced industrial countries. In the 1960s, according to the Toronto Star, “three dollars flowed North for every dollar flowing South; by the late 1990s, after 30 years of unprecedented growth and increasing globalization, the ratio had grown to seven to one” (William Rees, “Squeezing the Poor,” 4/22/02). For this reason, some developing country activists argue that globalization is a form of “recolonization.”
Other researchers talk about globalization in terms of the creation of a “transnational labor force.” A central aspect of globalization is economic integration — that is, the progressive merging of separate national economies into broader regional economies. Policies that promote “free trade” aim to create unified markets extending across national boundaries. For example, NAFTA (the North American Free Trade Agreement) creates a regional market system covering the United States, Canada, and Mexico. Depending on the specific situation, free trade agreements may establish multi-country markets in goods, services, currency flows, and investment capital.
The growth of international labor markets is an inevitable consequence of the expansion of international markets in investment, industry, and services. Usually, however, government policies treat labor very differently from these other sectors of the economy. The U.S. government, for example, actively promotes “free trade” with many different countries around the world. At the same time, however, it is just as active in seeking to restrict labor migration — often from the very same countries.
In practical terms, restrictive immigration policies cannot really achieve their stated objectives. The international economic policies promoted by the United States lead inevitably to increased immigration flows. At the same time, U.S. immigration policies impose criminal penalties on the people who make up these flows. For this reason, many people have argued that the true function of restrictionist policies is to depress wage levels, by creating a “gray market” in undocumented (“illegal”) workers who cannot risk demanding higher wages — or protesting abusive or illegal working conditions.
Undocumented immigration is not only a result of individual decisions; it has also become a permanent, structural feature of the U.S. economy. The situation is similar in many other parts of the world, especially in the advanced industrial countries. Many of these countries are grappling with controversies over immigration policy and undocumented immigration that are very similar to debates in the United States.
The global justice movement (also known as the anti-globalization movement) has challenged many different aspects of globalization. So far, however, it has paid relatively little attention to immigration and to movements for immigrants’ rights.
Family and Community
A third major reason that people leave their home countries is to reunite with family members. As with war refugees or international labor migrants, this category includes both legally documented and undocumented immigration.
Numerically, “family reunification” accounts for a large proportion of all legally documented migration. For example, in one recent year (fiscal year 1999), the INS Statistical Yearbook reports that nearly 650,000 people were granted legal residency. More than 475,000 of them were admitted under various categories of family sponsorship.
Those who do not meet official requirements must make a painful choice between entering the country without documents or involuntary separation from their families. As noted in the previous section, even permanent residents must meet income criteria to sponsor their family members. Even for those who meet the government’s criteria, the wait may extend to many years. People whose family relationships are not legally recognized — such as common-law relationships or same-gender relationships — are excluded from family unification programs. No statistics are available to chart the number of undocumented immigrants whose primary motive was to rejoin their families.
Creating the Future
In this brief overview of why people migrate, we have stressed the importance of international labor migration as the single most important “root cause” of immigration to the United States.
It is equally important, however, to remember that “labor markets” are made up of human beings. The social struggle for immigrants’ rights reflects the determination of immigrants to express their full humanity. For different people at different moments, this may mean reuniting with one’s family — or leaving an abusive or violent relationship. It may mean moving back and forth across borders to maintain ties with one’s family or country of origin — or it may mean building new communities that meet one’s needs for cultural, social, and material support. It may mean preserving cultural traditions — or developing new identities and new forms of expression. It may mean all of these things, and others as well.
The richness and complexity of human life and human community are also a root cause: the root cause of the universal thirst for dignity and justice. The lives of immigrants, like those of all people, are shaped by global economic forces. At the same time, immigrants, like all people, are also active, creative agents in the unfolding story of our world. These are the two faces of life, for immigrants — and for all of humankind.