The ugly dirty truth is that illegal immigrants form the underclass of the USA that allow for the relative cheap formation of small (otherwise noncompetitive) businesses when it comes to manual labor. Restaurants, cleaning, construction, automotive, farming, etc. It's a complete race to the bottom. But...if you can't stop people crossing the border...why not stop the people hiring them? Put them in jail?
But that's an incredibly unpopular solution. Every politician goes around orally fellating the small business ethos because it feeds into the meritocratic delirium. So essentially, Americans will backhandedly wail about illegal immigration while eating cheap fast food and hiring them to paint their walls.
There have been attempts to implement an ID system, especially when it comes to voting locally. But it was deemed racist. Because it meant only citizens who had the ID could vote. And some citizens didn't have IDs. And a portion of those people were poor minorities. And they didn't want to get them because it infringed on some rights. Or something. So America has this contrived system of registering to vote where people get tricked into also registering their political affiliation which is often used by politicians to sling mud at other politicians and political statisticians to pull slightly more accurate numbers out of their asses.
In some locales you straight up have to register with your affiliation to be able to vote. There's a significant segment of illegal immigrants who may or may not vote to support local political constituents that have their interests at heart, and a political party that appeals to those illegal voters. This political party uses this voter demographic for their benefit, because these local political constituents that are voted in have a voice in who the party as a whole can nominate for higher political parties. Since part of the political establishment is based on elections are based on representatives who then choose other representatives. And so the cycle continues.
Also, nobody wants to fucking pay taxes