Introduction America is going through a period of significant demographic changes. And it should not be viewed solely as immigration. It is not a secret that America itself is a society of immigrants. Even the first American settlers - American Indian tribes - were immigrants. Nowadays, the United States became an ''American dream'' to those who willing to go north for opportunity and live an American dream life, just by crossing the border legally or sometimes illegally just like large percent of Mexican immigrants... The need to understand the migration between United States and Mexico is greater today than at any time in its century long history. Its volume and complexity are greater than the most observes might have imagined even a decade ago; and it operates in a context charged with serious human, political and security challenges. The United States since continuously had strong concerns about immigration and the biggest disputes, which always were and exists nowadays - immigrants from Mexico. One debating side would stand, that wave of illegal immigrants from Mexico violate American economic and security interests, while others would believe that immigration to America brought prosperity, so to see just harmful side is inappropriate. So what are reliable estimates of the number of migrants, their legal status, and their rate of circulation? What role do Mexican migrants play in U.S. Labor force? The Heart of Mexican Immigration When the first Ukrainian Jew, Sicilian or Indian came to America, that person's arrival was a big geographical event; after all, it is interesting what he remembers about his motherland, which cultural aspects he values or how many miles took to come here? Generally speaking, these immigrants do not pose a threat to the geopolitical even by keeping their identity, which basic is only a memories about the countries left across hundreds or thousands of miles.. At first glance, it would appear that the influx of Mexicans should also be a welcome phenomenon. If people said that immigration is not a negative phenomenon, then why should U.S. oppose immigration from Mexico? The answer might not be so visible at the very first look, but Mexico' case is completely different and should not be seen as other migratory flows.. First of all, after immigrating to the U.S. Mexican do not terminate any geographical links and preserves continuity with the home-land. Mexican immigrant' roots are here, just at the border. The Italian, Jew or Indian would return to live back to his country only after leaving or destroying what was so hardly created in US. Meanwhile, the Mexican return does not creates major problems, as there is no remorse. If Mexican only would wish, he could spend his life without knowing in which of these states he actually lives or where is his roots. Perhaps it is important to talk about Mexicans, not as a nation, but take it as a geographical concept - as the "demarcation line". Because the U.S. and Mexico border is kind of demarcation line. As you know, America was ruling part of Mexican region since the Texas Revolution 1835-1836 till the Mexican War with the U.S. in 1846-1848. After the war, many of the areas previously belonged to Mexico, became a part of America. Eth