Meh, the Rio Grande is almost dry at this point.
I am a huge supporter of opening our borders. Primarily to those that have valuable skills/education, but all are welcome. Our immigration policy is flat out stupid in some places and poorly thought out in others.
Stupid - I know a number of foreign born PhD engineers and scientists who have had a lot of trouble getting citizenship. If you have a job that will sponsor you its not incredibly hard, but a lot of companies don't want to jump through the hoops to sponsor these people. This is apallingly stupid. Anyone who has a highly skilled education and can speak english reasonably well should be fast tracked to citizenship within a year. We NEED these people, we don't want them going back to their countries. We are the borg, we will assimilate you.
Poorly Thought Out - We want low-skilled/manual laborers. Right now we are outsourcing lots of jobs to other countries, its an unavoidable reality of the many countries that have rebuilt after the last century of wars, and the onset of capitalism in others. Luckily Europe is doing a good job of annhilating its own economy so we won't have to worry about competition with them for too long, but India, China, the Middle East and large parts of South America are going to become serious competitors with us in both manufacturing and the technical services industry.
We should be able to stay ahead in the technical services due to our university system, but a lot of people look at manufacturing as a lost cause. However, if we have a relatively open immigration policy we can increase the amount of people willing to do manufacturing in this country for low pay (which is the only way it will work), increase the amount of people buying all the stuff we manufacture, and create a labor drain in the other countries.
TLDR? Immigration is almost always a good thing in this country. This doesn't necessarrily apply to all countries. Europe has definite immigration problems but a lot of that stems from their over-the-top socialist policies, but in America, immigration is good.
Historically some of the largest immigration booms were followed/used in some of the most important periods of american history
Around the 1850's the Know Nothing's started talking about the dangers of all of the immigrants we were getting and tried to rally people to stop it. In the civil war, 25% of the Union Army were immigrants. Thank god the Know Nothings failed.
The Chinese built the American railroad system, of course right after that the Chinese Exclusion act completely stopped their immigration. Thank goodness we kept those yellow devils from building any more of our infrastructure. We clearly did something right there.
In the early 20th century there was a massive boom in immigration which was largely responsible for the Gilded Age industrialization of the United States. My bet is that we would have been much better off slowing down our industrialization, we would have been right on track for being competitive in WWII, and having a workforce capable of throwing us to the front of the pack right afterwards.
In a lot of those cases above, its pretty obvious that the immigrants were mistreated when they first arrived, and I'm not saying we should do the same. However, there are many many immigrants that would jump at the chance to come over here and work 2 jobs for minimum wage if they got citizenship, which wouldn't technically be mistreating them (I mean....it is a legal wage.)
So its not really mistreating, more that the first gen has lower standards of living which we can exploit for a cheaper manufacturing labor pool. After the first generation, we will start seeing more and more kids becoming technically skilled which then adds to our technical services labor pool.
And you want to know who complains about this line of thinking the most?
People that refuse to advance themselves from the manufacturing labor pool to the technical services pool. People who are, in fact, kind of a drain on our economy as they demand excessive wages for manufacturing jobs. So instead, we don't get the cheap labor and we send the work overseas.
By opening the borders we create the potential for an alternative to outsourcing, Insourcing. We import the cheap labor and do the manufacturing here. They will be naturalized and not mistreated, but will work a factory job building cars for 10$ an hour, and won't jump into some self-destructive union.
So that's my view. I am super pro-immigration, although its for reasons many of yall may find incredibly callous. I make no apologies for that. Many mexican's would be thrilled at the oppurtunity to do those manufacturing jobs in America for far far less than what we currently pay. That's not wrong to do, as what we currently pay is severely outvalued. And yeah, this would put a number of american laborers out of work (or at least cut their pay), but as far as I can tell that's going to happen anyways. I'm sure those people looking for work in Detroit are happy that they never took a pay cut.