The last amnesty was thirty years ago and has been shoved down the memory hole. You never hear pols talk about it. The press never asks about it, largely due to the fact they are too stupid to understand it. That and the lessons of the last amnesty reflect poorly on the current push to pass another one. Everything about American public life operates like a marketing campaign so the facts are flexible.

The most important lesson from that last amnesty is that the numbers presented by the government will be wildly underestimated. When it was passed, the pols said the high number for amnesty was a million. It turned out to be 3.2 million. This was not due to deception. It was ignorance. The people writing these bills rely on lobbyists who lie on spec. Just listen to the current presidential candidates talk and it is clear they don’t know the first thing about the topic.

There’s also the bias against frank talk. The political class is convinced they must lie to the public in order to avoid getting in trouble. It is not without merit. No one likes the bearer of bad news so if you’re in the vote getting business it is a good idea to avoid delivering bad news. Mass communications and modern behavior science techniques have us swimming in a sea of deception now, but that’s a topic for another day.

The point is we have a complicated subject that is not a lot of fun for the sensitive types who dominate our public debates. Add in the bias to paint a smiley face on everything and the only things we hear from our rulers are based on the best case scenario. Bearing that in mind take a look at some of the numbers in this Pew study.

In a reflection of changes in the overall economy since the Great Recession, the U.S. unauthorized immigrant workforce now holds fewer blue-collar jobs and more white-collar ones than it did before the 2007-2009 recession, but a solid majority still works in low-skilled service, construction and production occupations, according to new Pew Research Center estimates.

The size of the unauthorized immigrant labor force did not change from 2007 to 2012, but its makeup shifted slightly. The number of unauthorized immigrants in management or professional related jobs grew by 180,000, while the number in construction or production jobs fell by about 475,000, mirroring rises and declines in the overall U.S. economy. The share of all unauthorized immigrant workers with management and professional jobs grew to 13% in 2012 from 10% in 2007, and the share with construction or production jobs declined to 29% from 34%.

Despite these shifts, unauthorized immigrant workers remain concentrated in lower-skill jobs, much more so than U.S.-born workers, according to the new estimates, which are based on government data. In 2012, 62% held service, construction and production jobs, twice the share of U.S.-born workers who did. The 13% share with management or professional jobs is less than half of the 36% of U.S.-born workers in those occupations.

Unauthorized immigrants made up 5.1% of the nation’s labor force in 2012, numbering 8.1 million who were working or looking for work, according to previously published Pew Research estimates (Passel and Cohn, 2014). But as this new analysis shows, they account for a far higher share of the total workforce in specific jobs, notably farming (26%), cleaning and maintenance (17%), and construction (14%).

Now, there’s no way of knowing the exact number of illegal aliens. Pew is estimating the numbers from Census figures. It’s not perfect, but it gives us a clue as to how many people will be seeking amnesty. If we assume that at least some of these people are married and some of those have children, the 8.1 million figure is the absolute low end. The final number will be higher, but how high?

The easy thing to do is look at the last amnesty. If they were off by a factor of three the last time, we’re looking at close to 25 million this time. The last time they based the one million figure on total illegal population, not just those working. That means the 25 million could very well be a low estimate as well.

Then we have the fact that amnesty will invite swarms of new immigrants. This is exactly what happened in the 80’s. The hint of it last summer resulted in the Children’s Crusade that saw thousands of kids brought over the border by slavers. Immigrants know the rules better than the government officials so they will not pass up a shot to bypass all the rules and get that precious green card and the welfare benefits that go with it.

Then there is fraud. The current system is designed to fail. If you try to work the system honestly, you will wait in line for a decade to get in the country. The vast complexity invites fraud from both sides. The immigrants want to game the system rather than wait in line. The hacks in the bureaucracy just want to push paper around without breaking a sweat. The result is lots of fraud.

My own sense is Bush will collude with Boehner and McConnell to pass an amnesty of some sort. They will have to couch it in different terms and tart it up with phony-baloney enforcement language. The result will be the same. We will see 30-40 million foreigners handed citizenship papers by the end of the decade.

You better get working on your Spanish, esé.