"They should get in line and immigrate legally."
For would-be American citizens there isn't one single line. Each of the 195 countries gets its own line.
Imagine being at the DMV where there are 195 clerks at 195 individual windows. You are told to wait in the line that corresponds with your nationality. If you are from a country like Malta, Slovenia or Lichtenstein, you are in luck! You won't have much time to wait, since we get very few immigrants from Malta, Slovenia or Lichtenstein. If you are from Mexico or India you will confront a very long line, since many Mexicans and Indians want to migrate to America. Be ready to stand in line for decades. Seriously.
Furthermore, the law states that no more than seven percent of immigrants can come from any one nation. These immigration law limitations are called per-country caps. if you are in the Mexican line you will have to wait for at least 15 other people in the lines of the other nations to be served, otherwise you exceed allowable seven percent of the immigrants from your country.
U.S. immigration law imposes a limit on how many immigrants from any particular country can receive green cards in a given year. Under the per-country cap set in the Immigration Act of 1990, no country can receive more than 7 percent of the total number of employment-based and family-sponsored preference visas in a given year. There are no per-country limits for uncapped categories, such as immediate relatives of U.S. citizens.
Because of the numerical caps and per-country caps on certain green-card categories, there are significant waits for some categories, with sharper effects on a few countries. For example, as of April 2019, the wait for U.S. citizens to sponsor adult, unmarried children was more than seven years for most parts of the world, but was 12 years for relatives from the Philippines—and more than 21 years for those from Mexico. As of November 2018, there were 3.7 million people waiting in line abroad for a family-sponsored green card, and 121,000 awaiting an employment-sponsored green card. Source: MigrationPolicy.org
"We don't they immigrate legally like my ancestors did!"
If your ancestors were white, and they arrived in America after Columbus and before the early 20th century, they faced virtually no immigration restrictions.
In any debate about illegal immigration, that argument, with its implied moral distinction between prior generations of purportedly law-abiding immigrants, and anyone here illegally now, invariably comes up.
But although many people think their ancestors came legally, says immigration historian Mae Ngai, most families can't know that with certainty. And the criteria for admission to the United States have changed so much since the late 19th and early 20th centuries that most comparisons of then to now are like apples to oranges.
"Before World War I, we had virtually open borders," said Ngai, a professor of Asian American studies at Columbia University and author of the 2004 book Impossible Subjects: Illegal Aliens and the Making of Modern America. "You didn't need a passport. You didn't need a visa. There was no such thing as a green card. If you showed up at Ellis Island, walked without a limp, had money in your pocket, and passed a very simple [IQ] test in your own language, you were admitted."
A rapidly expanding America needed labor. One million immigrants were let in annually. Just 1 percent were turned away, typically because they failed the medical or mental test. Source: Philadelphia Inquirer
The Naturalization Act of 1790 declared that only people of white descent were eligible for naturalization, but was modified in 1870, when eligibility was extended to people of African descent in the wake of the Thirteenth and Fourteenth Amendments. Chinese and Japanese people were barred from immigrating to the U.S. in the 1882 Chinese Exclusion Act and the (unenforced) Gentlemen's Agreement of 1907, respectively. According to historian Mae Ngai, before World War I, the United States had "virtually open borders".
Most immigrants, perhaps your ancestors, were met with suspicion and contempt
People who were born in America, though of immigrant stock them themselves, greeted new immigrants with hostility and derision. "HELP WANTED. No Irish need apply" was a common sign and message at places of business. The treatment of Swedish immigrants was similar to the treatment other immigrant groups received. During the first waves of migration the Swedes were subjected to certain stereotypes and prejudices. He was dumb, clumsy, drank too much and talked with a funny accent. The immigrant historian Rudolph Vecoli has pointed out that they were not initially always recognized as "whites".
As Italians, Greeks, Russians, Poles, Hungarians, and other newcomers began showing up, said [Coulumbia professor and immigration historian Mae] Ngai, nativists leveled criticisms that "sounded much like the ones that you hear today: 'They don't speak English. They don't assimilate. They're darker. They're criminals. They have diseases.' " Source: Philadelphia Inquirer
Trump isn't unique in his anti-immigrant biases
"When Mexico sends its people, they're not sending their best. They're not sending you. They're not sending you. They're sending people that have lots of problems, and they're bringing those problems with us. They're bringing drugs. They're bringing crime. They're rapists. And some, I assume, are good people." –Donald Trump, presidential announcement speech, June 16, 2015
The usually fair minded Ben Franklin grumbled about German immigrants
"Those who come hither are generally of the most ignorant Stupid Sort of their own Nation."
"Not being used to Liberty, they know not how to make a modest use of it."
"Why should Pennsylvania, founded by the English, become a Colony of Aliens, who will shortly be so numerous as to Germanize us instead of our Anglifying them, and will never adopt our Language or Customs, any more than they can acquire our Complexion." --Benjamin Franklin. Source: Quartz.com
The 1917 Immigration Act was a low bar---as long as you weren't Asian
The 1917 Immigration Act, also known as the Asiatic Barred Zone Act, was a law passed by Congress on February 5, 1917 that restricted the immigration of 'undesirables' from other countries, including "idiots, imbeciles, epileptics, alcoholics, poor, criminals, beggars, any person suffering attacks of insanity, those with tuberculosis, and those who have any form of dangerous contagious disease, aliens who have a physical disability that will restrict them from earning a living in the United States..., polygamists and anarchists, those who were against the organized government or those who advocated the unlawful destruction of property and those who advocated the unlawful assault of killing of any officer." Prostitutes and anyone involved in or with prostitution were also barred from entering the United States.
A tax of $8 a head was imposed on immigrants, except children under sixteen accompanying a parent, and those over 16 who had not paid for their own ticket were prohibited from entering the country.
One of the key aspects of the 1917 Act was that people from what was called the Asiatic Barred Zone were restricted from entering the country. "Any country not owned by the U.S. adjacent to the continent of Asia" along specified longitudes and latitudes were restricted from immigrating.
Another important provision of the Immigration Act was the literacy test imposed on immigrants entering the country. Those who were over the age of 16 and could read some language must read 30 to 40 words to show they are capable of reading. Those who were entering the US to avoid religious persecution from their country of origin did not have to pass this test. Source: University of Washington Bothell, uwb.edu
Knowing what you know now, is it any wonder that people wade across the Rio Grande and hop the fence on our southern border? If you still aren't convinced that our immigration policy is unfair and counterproductive, perhaps John Oliver can explain it to you in his video below.