The consequences of immigration and the morality of restricting it are contested. You can see my views in these posts, among others:

• "The Hunger Games" Is Hardly Our Future--It's Already Here
• Benjamin Franklin's Strategy to Make the US a Superpower Worked Once, Why Not Try It Again?
• Us and Them
• You Didn't Build That: America Edition

Below are the views of the President of the United States, three economists and journalist Binyamin Applebaum, summarizing other views of the economists he interviewed about immigration, all taken from Binyamin Applebaum's article shown above. 

Donald Trump: 

• This legislation demonstrates our compassion for struggling American families who deserve an immigration system that puts their needs first.

Giovanni Peri: 

• The average American worker is more likely to lose than to gain from immigration restrictions.
• People have an outdated image [of legal immigration] ... It’s mostly Asian, Indian, Chinese people who are coming to do mid- and high-level professional jobs.

George J. Borjas

• [On reducing skilled immigration:] That is a political decision. That is not an economic decision.
• [On reducing low-skilled immigration:] If all you care about is economics, then it’s really clear. But do you want to live in a country that only cares about money, or do you want to live in a country that has a legacy of being generous to immigrants? Maybe you want a compromise.

Michael A. Clemens

• The story that ‘when labor supplies go down, wages go up’ is a cartoon.
• It’s a political myth that the principal need is for high-skilled workers.

Binyamin Applebaum

• One key reason is that immigrants often work in jobs that exist only because of the availability of cheap labor. Picking tomatoes is a good example. California farmers in the 1950s and early ’60s relied on Mexican workers even though machines were already available. In 1964, 97 percent of California tomatoes were picked by hand. ... By 1966 [after immigrant worker restrictions], 90 percent of California tomatoes were being picked by machines.

• A 2011 study found that high-skilled women were more likely to work in cities with high levels of immigrants, because families could pay for child care or elder care.

• The National Academy of Sciences made an ambitious effort to assess the bottom line in 2016. It concluded that the average immigrant cost state and local governments about $1,600 a year from 2011 to 2013 — but the children and grandchildren of immigrants paid far more in taxes than they consumed in public services.

In addition to annoyance at newcomers being different than what people are used to, immigrants are blamed for the fundamental truth that many people in the United States do not see their lives and their children's lives improving. The reasons behind the stagnation of life chances are complex. I wrestle with trying to understand them in "Restoring American Growth: The Video."

If I were to blame a group for this stagnation of life chances of many Americans, it would be the upper middle class, not the rich (who are a sideshow) and certainly not immigrants. In other words, I wish my own social class would engage in more self-criticism. A few modest sacrifices by us, the upper middle class, could make things much better for other Americans. For the short version of this argument, see "Steve Durlauf on Legally Encouraged Residential Segregation as a Perpetuator of Inequality" and "Keep the Riffraff Out!" We, the upper middle class, are good at articulately pointing the finger at others, but unfortunately find it hard not to see ourselves as innocent.