Immigration is a football wedge issue that cannot and will not be addressed.
The solution is already known, stricter enforcement of penalties for employers of undocumented workers. But that would actually fuck a sizable portion of the economy, as these workers are vital to a lot of low-wage labor (harvesting and food processing in particular).
Instead the plants and the feds play a game where the authorities give advance notice of ICE raids, and take a couple people and the employers face insignificant penalties.
As with any other mass behavior, adjusting it requires altering the economic incentives. People come here for higher wages, they come here illegally because the legal method is expensive, arbitrary, and time-consuming, and the opportunities open to illegal migrants are still enticing enough. Stopping illegal migrants requires removing those opportunities.
That might make some shareholders a penny less wealthy though, so we can't have it. We'll just keep arguing about this for the next 500 years and accomplish nothing, just be sure to vote for US because the other side wants to do the BAD THING on immigration.