But the bill makes employers jump through a lot of hoops to take advantage of this new labor pool. To hire a foreign temporary worker you have to pay a $2,500 fee, offer the worker the prevailing wage and (at the low-skilled end) show that you’ve tried to fill the job domestically. In many cases, that foreign worker will end up costing you more than an American citizen.

And, as Ana Avendaño, who handles immigration issues for the A.F.L.-C.I.O., points out, the bill introduces new safeguards against worker exploitation. Workers here on temporary visas are no longer captives of their sponsoring employer; they can change jobs. Workers cannot be deported for blowing the whistle on an abusive or unsafe workplace. There are new protections against human trafficking. The labor federation, with some misgivings, supports the bill.

The bill is especially — perhaps overly — generous to employers at the high end. Any foreigner who gets a graduate degree from an American university in science, technology, engineering or mathematics (STEM in the vernacular) and has a job offer can apply for a green card — even if he or she studied for a field that is already crowded with native job applicants. The bill would award permanent residence to anyone with a Ph.D. in any subject from any university in the world, if he or she has a job offer in that field. (“We want the smartest people here,” Schumer explains.) As the demographer Michael Teitelbaum points out, you can find shortages of skilled labor at some times, in some fields, and in some places, but over all there is plenty of domestic STEM talent looking for work. Teitelbaum suggests the bill would be improved by establishing an independent and authoritative panel, like the one in Britain that advises the government on adjusting the annual visa limits in different skilled specialties based on credible evidence about these labor markets. Schumer’s people say what works in Britain would be too cumbersome in a job market of 150 million workers. “By the time you gather the data, it’s old,” said Schumer’s immigration guru, Leon Fresco.

The nonpartisan Congressional Budget Office estimates that over the first decade the bill will have a negative but minuscule effect on employment and average wages. And then the influx of new workers will improve growth, create jobs and reduce the deficit. Other studies, from the Center for American Progress on the left to the Cato Institute on the libertarian right, have also concluded that the long-term economic effect is positive and substantial. All of these estimates are more than a little speculative, depending on human behavior and government enforcement. But most experts agree that the country will ultimately benefit, as it has in the past, from being the preferred destination of the ambitious, the industrious, the brave, the new.

And as the bill supplies new streams of legal labor, it attempts to restrict the flow of illegal labor. As Doris Meissner of the pro-reform Migration Policy Institute notes, “It replaces a laissez-faire illegal system with a regulated legal system.” Which brings us to ...

CONTROLLING THE BORDERS The $46.3 billion earmarked to double the size of the border patrol, raise fences and install monitoring technology on our Southern flank is a nice stimulus package for border states and a windfall for a few favored technology companies, but it is mostly for show. Forty-percent of those here illegally didn’t jump a fence; they simply overstayed a student or tourist visa.

By far the most promising control measure in the bill is one business hates, one that has been overshadowed by the border fortification boondoggle: mandatory employer verification. Employers will now be held accountable for verifying that anyone they hire has a legal right to work here. It replaces the current voluntary system, which is almost universally ignored, with real penalties and real enforcement. Foreign workers will be required to have a tamper-proof ID, including a photo and a fingerprint. Citizens can use a driver’s license or a voter ID. The bill also launches a project to design a fraud-proof Social Security card. Some inventive employers will find loopholes. But there are plenty of teeth in those 1,198 pages.