As the past 4 years have demonstrated, there is a very large segment of the US population is very much against immigration, and would happily turn the country into an "island" by building walls around the land borders.
The exact amount of immigrants and the requirements to come here legally is less uniform in acceptance.
The biggest issue is between legal and illegal immigration.
Among the Republicans, the 40% who are anti-immigration tend to feel very strongly about it, and are likely to consider it a major issue. The 60% of Republicans who are OK with immigration are less likely to consider it a major issue.
This makes it hard nowadays to get Republican support in the House for pro-immigration policies, because a pro-immigration Republican member of the House will attract anti-immigration primary challengers who will get the vote of the 40% who are anti-immigration. With that big bloc in hand its hard for the challenger to lose.
You can see a similar thing with abortion. About 60% of Republicans favor keeping Roe v. Wade, about 30% want to overturn it, and the rest are unsure [1]. But how many Republican members of Congress will come out or vote in favor of keeping Roe v. Wade? Pretty close to zero because doing so is political suicide in their next election.
[1] https://www.npr.org/2019/06/07/730183531/poll-majority-want-...
I thought Canada was far easier. I knew a software engineer who, about 15 years ago, got the Canadian equivalent of a green card as a "backup" without ever having actually lived there, in case she had problems with her US immigration. It sounded like a box ticking exercise, though this person had two masters degrees (IIRC, the second was to keep her status since she graduated from the first into a recession).
If you try to illegally immigrate into Canada, they will deport you
To list a few different people find concerning: depressing wages of domestic population, rapid cultural change of domestic population, brain drain from foreign population, strain on tax / social systems, ineffective vetting allowing cross-border contraband and criminal activity, and so on.
All of these are valid and deserve scrutiny and investigation. Obviously there are many beneficial aspects to immigration, and nearly all examples of very successful civilizations in history were at a crossroads of many cultures. Just wanted to make it clear that the immigration debate won't "die with boomers", and it shouldn't, because it is an important discussion to have.
Moreover, mostly in the places where productivity is not happening. Their growing irrelevance and sociocultural aversion to change are primary reasons for their vocality.
1. Dying out.
2. Not in places immigrants want to immigrate to.
There's reason to doubt that. A lot of Trump's support was rural, and a lot of immigrants are farm laborers.
