The Mexico immigration and economic issue is going to be an absolute disaster. I’ll give you some history and show how it will play out in the future.
Mexican immigration to the US is guided by economic conditions within Mexico. When people can make significantly more money in the US, illegal immigration is a giant issue. Hundreds of thousands of people cross the border illegally in order to get more work. When Mexicans can make relatively good money in Mexico, illegal immigration is largely a non-issue.
Since the last major economic downturn, illegal immigration has been a non-issue. Economic conditions within Mexico has made it so it is much more valuable for people to largely stay there. Net-immigration to the US from Mexico is nothing (just as many illegal immigrants coming as going). People think it is an issue due to certain media outlets, but it is merely a shadow of history. The leftover major problems are a result of the drug-war, not of people searching for work.
Here are a couple of major economic realities. Mexico needs the US markets more than the US needs Mexican products. 80% of products made in Mexico get sent to the US. A 10% tariff on Mexican goods would price them out of the market on certain products and would hurt their economy vastly more than 10%. However, the Trump administration is suggesting a larger tariff (20%). While tariffs on Mexico would greatly hurt the US economy, it would be vastly worse for Mexico. Since this conflict has occurred, the Mexican Peso has tanked.
Trump knows he has Mexico over a barrel. The economic leadership of Mexico knows Trump has them over a barrel. Mexico is utterly fucked economically if things keep going in the direction they look like they are going.
The irony of this all …. we will be flooded with illegal Mexican immigrants. Since the US dollar will have so much more value, people will work here and send money back to their families in Mexico.
Since they plan to toughen up border security, it merely means things will get vastly more dangerous, corrupt, and hostile on the border. The results from conservatives will be more security and that will just result in more danger, not less immigration. This is the same sort of cycle and consequences as the drug war.
The current course Trump desires to take will lead to more border violence and more illegal immigration. What keeps Mexicans in Mexico is a vibrant and successful Mexican economy. When you obliterate their market with tariffs, they will be clamoring over the border at any expense.