I share Ramesh’s perplexity about the reaction of supporters of the Senate immigration bill to the two CBO reports released yesterday. Although they contain some helpful projections on the economic and fiscal fronts, the reports undermine the case for the bill in some pretty fundamental ways.

First of all, on the question of illegal immigration: As I understand the CBO reports, they’re saying that, if the bill passes, then 10 years from now, after we have gone through all the effort and political combat involved in offering legal status to today’s 11 or 12 million illegal immigrants, there will be somewhere around 7 or 8 million illegal immigrants in America—3.5 million who did not get the new RPI status (presumably most but not all would stay here), and 4.8 million who entered illegally after the law was enacted. And the number will still be growing pretty quickly. Indeed, they expect more people to enter the country illegally in the next decade than did so in the last decade. With the triggers and enforcement provisions of the bill as they are, I don’t think it’s possible for anyone to claim that it will meaningfully address the problem of future illegal immigration. At the very least, you can’t say so without explaining why the CBO got things very wrong.

And second, it’s important to appreciate the sheer volume of new immigration that CBO is projecting as the premise behind its cost and revenue estimates, as Reihan has noted today too. If you make a mid-range estimate of the baseline current-law immigration projections that CBO is making (they don’t specify what they are, but the latest Census projections combined with this explanation of CBO’s methods of projecting immigration flows allow for a good guess), you’d have to say that they expect somewhere around 9 or 10 million new immigrants to come to America without the new law passing. They then say that the law, if it passes, will yield a net addition of 10.4 million to that number (about 12 million more new legal immigrants than otherwise would come, but about 1.6 million fewer illegal immigrants). That means you’re looking at roughly 20 million new immigrants in one decade, so that immigration over the next decade would be roughly double what it was over the past decade. And although CBO is not specific about the skills distribution of these new immigrants (saying only that “a greater number of immigrants with lower skills than with higher skills would be added to the workforce”), the category breakdown of this unprecedented influx suggests it would be fairly heavily weighted toward low-skill immigrants.

That projection isn’t an argument. It doesn’t mean we shouldn’t proceed. Immigration is good for America, but we govern and shape it with laws for a reason: Like all things, it is good up to a point, and it is better in some forms than in others. Have we thought through the volume of immigration that would result from this legislation? Have we thought through its balance of skills? Should we not hear a case for doubling American immigration over the next decade before we go ahead and do it? Has anyone argued for that? To what problem would such a huge increase be a solution? Does anyone have the sense that this is what our immigration debate has been about, or even quite understand that this is what the bill would do?

When the Hart-Celler immigration reform was enacted in 1965, creating today’s immigration system, everyone focused on the shifting of visa categories to finally put an end to racist quotas, and few people predicted that the law would dramatically distort the legal immigration system in the direction of massive chain immigration. It seems to me something similar is going on here—because we are focused on the question of offering legal status to illegal immigrants, we may be missing what this bill will really amount to in practice and what will matter most about it.

In any case, I think yesterday’s CBO reports are very important. The projections they make about economic effects (although they acknowledge they are premised on evidence drawn from much smaller waves of immigration than the one they project) and fiscal effects should help proponents of the law. But the projections they make about illegal immigration should put an end to any notion that this law will address that problem, and the projections they make about overall immigration levels should lead us to think about how much and what sort of immigration would be best for the country.

I think these five changes to the bill, which I proposed last month, would help address its key flaws—including those made all the more clear by CBO. But even if they don’t agree with me that a rebalancing of the bill’s approach to labor-based immigration is necessary, the law’s proponents should certainly be made to explain why they think its triggers and enforcement provisions will perform far better than CBO expects. As the CBO’s findings sink in, I suspect they will be seen as a major impediment to the prospects of this particular bill.