Prohibition didn't work

There are huge differences between Prohibition and trying to stop illegal immigration. Those who claim that Prohibition's failure implies the failure of stopping illegal immigration are either lying to you or are unable to think things through.

• Illegal labor: Almost all illegal aliens work for companies, and the U.S. government has detailed information available on almost all companies that are able to hire illegal aliens. Those companies have filed various documents with federal, state, and local governments, they have fixed locations, headquarters, offices, and the like. They operate out in the open, with published addresses for their plants and factories. In many cases, companies that employ illegal aliens are major corporations.
• Prohibition: The location of a speakeasy was not published. The location where hootch was sold wholesale was not sent to the federal government.
• Illegal labor: Those who perform the work are people, and as such they're a bit difficult to hide.
• Prohibition: Booze can be hidden in everything from a small flask to a large drum.
• Illegal labor: Illegal aliens have to be dealt with lawfully, perhaps including being given a hearing and deported in a legal fashion. While they're here, many have children who, under the current interpretation of the 14th Amendment, are U.S. citizens. Very few illegal aliens have given up their allegiances to their home countries, providing a power base for those countries inside the U.S.
• Prohibition: Liquor is an inanimate object and can be flushed down the drain if not wanted. It doesn't have allegiances to other countries and it doesn't have political ideologies. It just sits there.
• Illegal labor: Illegal aliens work for at least a few hours for one employer, and sometimes the working relationship lasts months or years.
• Prohibition: Selling liquor was generally a quick, shadowy transaction between two parties who may have never seen each other before and who may have never seen each other again. It wasn't performed out in the open.

The only way in which today's trade in illegal labor is similar to the trade in illegal liquor involves things like massage parlors, sweatshops, and street corner day laborers. However, those are a relatively small part of the illegal labor market. And, even those employers have known physical locations, business licenses, etc.

And, we still have "Prohibition" of a sort: some forms of liquor are illegal, the production and import is tightly controlled, and there are various other labeling and advertising requirements. Unlike with illegal immigration, the government is quite willing to enforce those laws and, as a direct result, there is very little questionable liquor being sold. Executives at major corporations are not willing to risk the fines and perhaps even imprisonment associated with breaking those rules. And, the government is willing to draw a bright line between what's legal and what's not. In the case of labor, the government leadership is much less willing to do its job.

Some substitute the War on Drugs for Prohibition, and similar arguments apply in that case. Some bring up the market in forged documents. Since those are almost always used by illegal aliens, similar arguments apply there as well.