A massive invasion from Mexico into the United States is currently underway - or at least that's what some political and media pundits would have us believe.
"There is an invasion of the United States going on. We wouldn't have 12 million illegal aliens here if there wasn't an invasion," Fox News' Bill O'Reilly has said on more than one occasion.
But history is not on his side.
For starters, illegal immigration has slowed to a trickle, with border crossings dropping more than 80 percent between 2000 and 2010. According to the Pew Hispanic Center, there were 11.2 million undocumented immigrants living in the United States in 2010 - a sharp decline from a peak of 12 million back in 2007. The decrease, first visible in 2009 when the number was 11.1 million, represents the first significant reversal in the growth of this population over the past two decades, with the economic downturn mostly responsible for that.
Photos: 60 years on the U.S.-Mexico border
- Take a look back at over 60 years on the border, from the agents that protect it to the people that try to avert it. This slideshow is part of Myth vs. Facts, a special series from Viva Colorado about immigration.
And then there's the issue of immigrants as a percentage of the total population of the United States.
While the 2010 Census says 40 million immigrants - from naturalized citizens to undocumented foreigners - call the United States home, there are far more people in the overall population, about 200 million more, than at the height of European immigration in the early 1900s.
"The numbers are larger now than they were in the past," said immigration expert Kitty Calavita, a professor of criminology, law and society at the University of California, Irvine. "But if you're talking about percentage of foreign-born relative to the U.S. population, (it's) simply not true that there's a larger percentage of foreign-born in the population today."
At the turn of the 20th Century, as a percentage of the U.S. population there were more immigrants then - 14.8 percent - than now. The most updated numbers, from the 2010 Census, show that the percentage was 12.9 that year.
So why insist that the current wave of immigration is unparalleled?
"During every period when there has been anti-immigrant backlash, it's always imagined that this is an unprecedented situation," said Calavita.
Photos: The Bracero Program in Colorado
- Generations of Braceros, temporary guest workers from Mexico, came to Colorado under a series of bilateral laws between the Mexico and the United States. This slideshow is part of Myth vs. Facts, a special series from Viva Colorado about immigration.
History professor Guadalupe San Miguel of the University of Houston agrees.
"Benjamin Franklin was the first one that made those kind of comments when he started arguing that the Germans were overrunning the British and that they had to put a stop to it because they were diluting the British blood," San Miguel said.
While most of today's anti-immigrant sentiment is directed at Latinos, currently the largest immigrant group in the country, Europeans faced a similar kind of discrimination in the not so distant past. According to a classified ad in a New York City newspaper in 1895, Italians were paid less than both blacks - up to 15 cents less - and whites - up to 25 cents less - for the same type of common labor.
The same thing happened to the Irish, who came in droves during the Potato Famine of the 1840s and '50s. In spite of their skin color, "they were associated with blacks in this country because of their poverty and the kind of work they were forced to do," said Calavita.
Plus, the Irish had religion working against them. The Know Nothings, a nativist political party made up of Protestant Americans who feared that an increased Catholic population would place them under control of the Pope, fought hard to stop immigration. In 1855, the Know Nothing mayor of Chicago barred all immigrants from city jobs.
Sound familiar? In the past few years, several states - including Arizona, Alabama and Georgia - have passed extremely strict laws in an attempt to slow the flow of illegal immigration.
In 2011, Alabama passed what are considered the harshest anti-immigrant laws in the nation, with provisions that require law enforcement to check the legal status of anyone they suspect of being undocumented, that mandate that public schools check the legal status of students, that abrogate any contract made with an undocumented immigrant and that make it a felony for undocumented immigrants to contract with a government entity.
All such anti-immigrant laws are being challenged in the courts because many argue that their measures, including those that would essentially allow racial profiling to determine a person's immigration status, violate civil rights.
"Some people simplify the issue and say, 'Well, the reason why there's so much anti-immigrant backlash today is because we have so many Mexicans, and Americans are racists," said Calavita. "It's not that simple because historically no matter what group comes in, there's a racialized backlash against them."
So history repeats itself. And people don't learn from history.
"People wish to express their biases without feeling guilt, and that's the best way to do that," said San Miguel. "You demonize, you dehumanize the people you want to attack. You make them into a threat, then it's easy to attack them."
Even though this country owes a great debt to immigrant labor, according to both Calavita and San Miguel.
The United States has always depended on immigrants for a cheap workforce. The Chinese, for example, were largely responsible for building the first transcontinental railroad. But then after the Civil War, when the Chinese Exclusion Act of 1882 passed restrictions on immigration from China, the United States turned to Mexico for low cost workers. And that was only the beginning.
"If you look at the history of immigration it becomes very clear that immigrants were welcomed to the extent that they could provide cheap labor for jobs that other people didn't want to do," said Calavita.
The U.S. government has consistently encouraged and facilitated Mexican immigration - especially during times of labor shortages caused by major wars.
"Americans imagine that this is a one-sided situation, that Mexican immigrants push to come into this country," said Calavita. "But there's never a sense that the United States itself has been the recruiter for labor and encouraged it."
Even though there are numerous examples of just that.
One such time was during World War II, when the United States and Mexico entered into a bilateral guest-worker agreement known as the Bracero Program to meet a labor shortage created by the war. It basically imported Mexican immigrants to work in agriculture for a specific length of time with the explicit understanding that once their contract expired they had to return to Mexico.
Initially intended to last through the end of the war, the constant influx of low-cost, no strings attached labor kept the program going from 1942 to 1964. In that time, more than four million contracts were extended to Mexicans pickers.
"Its popularity resided in its ability to provide immigrant labor-power without making people citizens and being able to send people back to Mexico whenever they weren't needed anymore," said Calavita, author of "Inside the State: The Bracero Program and the INS."
But eventually the program's exploitation, broken contracts, subhuman working and living conditions and reduced wages were revealed, she said. In 2008, tens of thousands of braceros won a lawsuit for unpaid wages.
This "legal" guest-worker program also gave rise to massive illegal immigration. It's estimated that throughout the duration of the Bracero Program, the possibility of work lured hundreds of thousands of Mexicans to enter the U.S. illegally. Once here they were put right to work by the agriculture sector, which had no problem hiring them at even lower wages and avoiding all the red tape associated with the Bracero Program, Calavita said.
In 1954, in the name of anti-communism, the United States implemented a program officially called "Operation Wetback" that successfully deported more than one million undocumented Mexican immigrants - and many Mexican-Americans citizens.
"The United States wasn't being overrun by communists, but it didn't really matter in terms of how people thought about immigrants.," Calavita said.
More than 50 years later, not much has changed.
In 2011, the Obama administration deported a record number of undocumented immigrants. The projections for this year call for the number to surpass 400,000 for the first time in history. Even so, the immigration debacle continues.
Despite petitions from both sides of the issue, even George W. Bush was unable to deliver comprehensive immigration reform. President Obama promised to continue pressing for such reform during his campaign, but he's been unsuccessful in passing even the Dream Act, considered one of the least contentious proposals related to immigration.
And so it appears that comprehensive immigration reform will continue to be as elusive as always.
Did you know?
Although it has been illegal to be an undocumented worker since 1929, it didn't become illegal to hire one until more than 50 years later in 1986.
In 1907, the Expatriation Act declared that if an American woman married a foreigner she would lose her citizenship.
Most foreign-born residents in 1910, spoke German, Italian, Yiddish, Polish or English. Spanish didn't enter the picture as one of the most spoken ones until 1960.