But that's all "compared to current law." So what's current law?
The Census Bureau already expected net international migration to increase by roughly 20 million in the next two decades.* The 16.2 million extra people that CBO expects immigration reform to attract are on top of that. So, if the Senate bill passed, the United States would be adding somewhere around 36 million new immigrants over the next two decades — a figure comparable to the population of Canada.
But it's not just the raw number of immigrants that will change. Who those immigrants are, and whether they're here legally, will change too. This helpful table from the CBO tells the tale. It projects the growth in U.S. population over the next 20 years compared with what would happen if no bill passed at all. (This isn't as confusing as it first looks; we'll walk through it below):
To make this all more concrete, let's look at what the CBO expects to happen in 2018, just five years from now, if the Senate bill is passed. Remember, these are just estimates, but they're useful illustrations all the same:
1) The U.S. population of illegal immigrants in 2018 would shrink from roughly 14 million to about 5.5 million. Most of this drop would be due to the fact that 7.7 million unauthorized residents would receive amnesty and become newly legalized. But tighter border security would also reduce inflows somewhat.
Let's start with the big picture: There are currently an estimated 11.5 million illegal immigrants living in the United States. Past CBO projections had suggested this number will rise to roughly 14 million by 2018 if we stay on our current course, although predictions here are always hazy.**
Now let's say the Senate bill becomes law instead. Then in 2018, CBO predicts, 6.3 million of those unauthorized immigrants would apply for and receive “registered provisional immigrant" status, which requires paying a $1,000 fine and other fees. These immigrants could stay and work in the United States but wouldn't receive any federal benefits. After 10 years, they could apply to become permanent residents.
An additional 1.4 million currently unauthorized farm workers (and their families) could apply for special "blue cards" after paying fees. This would enable them to stay and keep working in the United States, with the option of applying for residency after five years.
Meanwhile, the CBO expects that the annual flow of new illegal immigrants would drop by about 25 percent. Now, that's just a guess — other experts I asked thought the real number could be much higher or lower in any given year. On the one hand, beefed-up security measures would tamp down border crossings. But there'd also be more immigrants who overstay their temporary visas under other newly established programs. Put these together, and the CBO thinks the unauthorized population would shrink by an estimated 700,000 people in 2018.
So, under the Senate bill, that would still leave roughly 5.5 million illegal immigrants left in the country five years from now (give or take a few million). These are mostly people who don't qualify for the amnesty provisions. This number would either shrink or keep growing very slowly in the years ahead, depending on how effective those various security measures proved to be.
Meanwhile, some Senate Republicans are now talking about an amendment to add even more money for border security, so these numbers could shift further.
2) An additional 5 million legal immigrants would enter the United States over the next five years. Again, this is over and above the roughly 4.5 million legal residents and temporary workers that the United States was already projected to add.*** Here's how that breaks down:
-- By 2018, an extra 700,000 immigrants would arrive legally through family-based visa programs. That's because the Senate bill would allow spouses and children of legal residents to apply for a green card in the near term, but would then slowly reduce the cap for family visas over time.
-- An additional 1.1 million immigrants would arrive through new employment-based programs. That's because the Senate bill would allow more high-skilled and highly educated workers to enter the United States without counting against the existing cap on visas.
-- An additional 2.5 million immigrants would come in through a "merit-based program" that awards visas based on a point system. This part of the Senate bill would try to cut through the current backlog of applications. Many of these new immigrants would be relatives of current legal residents.
-- Then there's an extra 900,000 temporary workers entering the country by 2018. This includes 100,000 extra high-skilled workers with H1-B visas and 300,000 extra low-skilled and farm workers under the W-visa program.
Put it all together, the CBO finds, and there are 12.7 million additional legal residents in the United States by 2018 if the Senate bill passes. About 7.7 million of those are previously unauthorized immigrants who received amnesty (as described earlier in this post). And 5 million are new people from abroad who wouldn't otherwise have come here and their children.
3) Legal immigration will continue to expand in the future — with high-skilled immigrants making up a small fraction of the total.
Again, we're assuming the Senate bill passes. The number of additional legal residents in the country goes up an extra 12.7 million in 2018, then to 18.5 million in 2023, and then to 24.1 million in 2033. (Again, this is over and above the legal immigration that was already expected.)
A few things are happening here as time goes by. Many amnestied immigrants who received provisional status become permanent residents. The number of legal immigrants who come through employers rises — to an extra 5.1 million in 2033. And the two "merit-based programs" to cut the backlog expand significantly, bringing in family members of existing residents, people who speak in English, people with education, and people from countries that have had little that have had little immigration to the United States.
Note that the number of high-skilled immigrants and temporary workers also rises, though not quite as quickly as the number of low-skilled workers. The H1-B program, for instance, doesn't expand as quickly as programs like the W-visa for farm workers and low-wage workers. And the Merit-Based Track 2 program, which clears much of the family backlog, expands more rapidly than the employment program, which includes a lot of high-skilled workers.
* A note on baselines: The CBO's analysis of the Senate immigration bill looks at what would happen "compared with current law." Trouble is, the CBO doesn't publish a detailed forecast of what it expects immigration to look like under current law, and the office declined to provide their baseline to me.
So I had to make an educated guess. The Census offers a range of scenarios for what future immigration could look like — it's "middle series" predicts about 20 million net new immigrants between now and 2033. The CBO has said that it has its own projections that differ "somewhat" from the Census, but they don't list exact numbers year by year.
** Unauthorized residents baseline. CBO estimated back in 2011 that it expected the net inflow to surge to 1.4 million in 2014 and 2015 as the economy recovered. That would then slow sharply and reach just 270,000 a year by 2020. So it looks like the CBO expects the unauthorized population to grow from 11.5 million today to somewhere around 14 million in 2018 under current law. Again, though, without precise figures this is just an educated guess.
*** Legal immigration. In its 2011 report, CBO projected that the United States would add around 800,000 to 1 million legal immigrants each year between now and 2020, a figure that includes both permanent residents and temporary workers. This is roughly in line with estimates from the Social Security Administration.