Also, I'd like to note people had the same fears about Italians in the 1910s, Germans in the 1890s, and the Irish in the 1850s.
That's the standard leftwing ridiculous comparison. Those people came LEGALLY, not creeping over the border at midnight. Many brought needed skills - they weren't illiterate rural peasants. There wasn't 20 million of them in a very short time frame. They didn't virtually take over a whole section of the US, and virtually make it a province of germany. They didn't fill the jails. There was no welfare state to loot. They didn't bankrupt the ERs. They were determined to become americans and learn english as soon as possible, as opposed to mexicans who've been here 30 years, can't speak a word of english, and don't need to in a city (los angeles) where the mayor gives speeches in spanish.
You have NO IDEA what you're talking about.
So much misinformation and so many inaccuracies in your post.
1. Late 19th/early 20th century immigrants came here "legally" in sense that the United States did not have laws barring their entry (with the exception of the Chinese). They weren't forming some orderly queue.
2. Most of those early immigrants crowded in to tenements and worked in sweatshops in large cities. Hardly a skilled labor force.
3. They definitely took over large portions of the country. The upper Midwest today is still dominated by lines of Scandinavian immigrants. Every major city in the East had a Little Italy and a Greektown.
4. The proportion of crimes committed by Hispanics in the US matches closely to their share of the population and their economic status. In fact, studies have shown illegal immigrants are less likely to commit crimes.
5. Hispanic immigrants in the United States learn English. While first-generation Hispanic immigrants do typically have trouble learning the language, 90% of their American-born children are classified as speaking the language "very well" and most of the third-generation can't speak Spanish at all. (Most third-generation Latinos speak English with ease, Pew poll shows | Riverside | PE.com | Southern California News | News for Inland Southern California)
6. Politicians have always pandered to minority communities. Go read about New York City politics in the early 20th century, or even Chicago politics today, where divisions between the Irish, African-Americans, and the Polish still play a big role.