The Hoeven-Corker border security amendment to the Gang of Eight comprehensive immigration reform bill is finally out, and it is huge. Released in several parts, it totals 1,190 pages, amounting to a rewrite of large portions of the original bill. While much of the text of those 1,190 pages duplicates portions of the original legislation, there are entirely new passages and significant changes throughout — enough to keep anyone who cares about what is in the bill busy for quite a while.

The problem is, they don’t have quite a while. The Senate will likely vote on the amendment on Monday. That’s not much time to read and digest such a momentous and far-reaching piece of legislation.

On Friday, Republican Sen. Bob Corker anticipated such concerns and sought to reassure the public by saying that everyone will have 75 hours to read the amendment before the vote. “I know we have had a lot of people on the floor who have criticized this legislation without reading it,” Corker said. “I know it has been called a magic amendment. I will just say to people who care about border security — and obviously numbers of people on our side of the aisle care deeply about that — read the bill. By filing cloture today [Friday] on this amendment, it is going to give everybody in this body and in the nation the opportunity to read this piece of legislation for 75 hours before the cloture vote occurs.”

If one started as Corker spoke and devoted 16 hours a day to nothing but studying the bill, one would have to cover about 24 pages an hour to finish the legislation. That’s certainly doable — if one has 16 hours a day for three days to do the job. But it’s also not easy, because reading the amendment requires comparing the new text to the original text of the bill to try to spot changes. Despite what Sen. Corker says, it’s not a lot of time.

Several Senate staffers are going over the amendment this weekend. Sen. Mike Lee, for example, has assigned staff 100-page sections of the legislation in a hurried attempt to know what’s in the entire bill. For my part, here is an early look at some of the bill’s major changes.

First, the bill does not alter the fundamental legalization-first structure of the original Gang of Eight bill. The nation’s estimated 11 million illegal immigrants will be granted legal status within months of the bill becoming law, before enhanced border security and interior enforcement measures are in place. But the bill does put in place new requirements that those measures be finished before millions of legalized immigrants can move on to permanent legal resident status — green cards — and ultimately to U.S. citizenship. Even so, there remain some of the exceptions and waivers that critics pointed out in the original bill.

On the enforcement side, the biggest change is the so-called “border surge.” The legislation gives the Secretary of Homeland Security eight years, until September 30, 2021, to “increase the number of trained full-time active duty U.S. Border Patrol agents deployed to the Southern border to 38,405.” How they chose the specific figure of 38,405 is unclear, but that’s what the bill says. The legislation also sets a date — September 30, 2017 — for the hiring of 3,500 new Customs officers.

Hoeven and Corker also require new border fencing, although not always double-layer fencing, as many border security experts have advocated. The bill does not specify a deadline date for completion, but it requires that the Secretary of Homeland Security be able to “certify that there is in place along the southern border no fewer than 700 miles of pedestrian fencing which will include replacement of all currently existing vehicle fencing on non-tribal lands on the southern border with pedestrian fencing where possible, and after this has been accomplished may include a second layer of pedestrian fencing in those locations along the southern border which the Secretary deems necessary or appropriate.” Where the fence goes up is entirely at the Secretary’s discretion.

As far as other security measures are concerned, the Hoeven-Corker amendment is far more detailed than the original bill. The idea was to take away the discretion of the Secretary — many Republicans have expressed skepticism that current Secretary Janet Napolitano and President Obama will actually do the work — and dictate new security measures within the bill itself. The new amendment does that. So, for example, it includes these requirements for the Yuma and Tucson sectors of the Arizona border:

(i) 50 integrated fixed towers.

(ii) 73 fixed camera systems (with relocation capability, which include Remove Video Surveillance Systems.

(iii) 28 mobile surveillance systems, which include mobile video surveillance systems, agent-portable surveillance systems, and mobile surveillance capability systems.

(iv) 685 unattended ground sensors, including seismic, imaging, and infrared.

(v) 22 handheld equipment devices, including handheld thermal imaging systems and night vision goggles

The amendment includes similarly specific requirements for each of the nine sectors of the U.S.-Mexico border. It also includes changes in provisions involving the E-Verify employment system and the exit-entry system to check for people who overstay visas that allow them to come into the U.S.

The amendment has a huge price tag. Whereas the original bill allocated $8.3 billion to what is called the Comprehensive Immigration Reform Trust Fund, the new bill provides $46.3 billion.

So the question is: Does the bill absolutely require that all of those measures must be in place and actually working before legalized immigrants can move to green card status? The answer is mixed. Yes, it requires the measures to be in place, although there is usually a waiver or exception nearby. But no, it does not require them to be working in some measurable way before immigrants are awarded green card status.

The new language in the Hoeven-Corker amendment says that, with the exception of agricultural workers and so-called Dreamers who are given fast-track status in the bill (that’s more than a million people right there), the Secretary of Homeland Security may not move immigrants from provisional legal status to permanent status until six months after certifying that what is called the Comprehensive Southern Border Strategy, with its various provisions for Border Patrol, Customs, fencing, surveillance technology, E-Verify, exit-entry and more, “is deployed and operational.” It further defines “operational” as meaning that all the security measures have been “procured, funded, [and are] in current use by the Department to achieve effective control, except in the event of routine maintenance, de minimis non-deployment, or natural disaster that would prevent the use of such assets.”

That is a major change from the original bill, which not only did not define the Border Strategy but required only that it be “substantially deployed and substantially operational” before immigrants were granted permanent status. That could have meant virtually anything.

So the new amendment is tougher on that front. But the fact is, Hoeven and Corker — and many Republican colleagues — intended it to be much tougher than that. As originally conceived, the amendment would have required proof that the new security measures are actually working, in a measurable way, before immigrants could move to green card status. “For all of the people that they identify coming across the border, you’ve got to capture or turn back 90 percent of those folks,” Hoeven told me in a June 17 interview. “And only then can you go from registered provisional immigrant to green card status.”

That 90 percent standard — a measurement of results, not just effort — was unacceptable to Democrats. Several reports in the last few days have said that President Obama told Senate Democrats that a 90 percent standard was a deal-killer. Of course, the Democrats already thought that themselves, as did the immigration activist groups that support them. Throughout the course of negotiations, from the Gang of Eight’s beginning until now, Democrats have resisted any provision that would require measurable border security before immigrants are granted green card status.

And Republicans have given in. The thinking behind the new amendment seems to be that it throws so much money at the problem that it is bound to increase border security significantly, even if not in a way that can be certified 90 percent effective. So Republicans accepted the Democrats’ offer of lots of new spending on security in place of the 90 percent standard.

Finally, the Hoever-Corker amendment includes a provision that has been in the bill from the start, which says that if litigation or some unspecified act of God delays implementation of the new security measures, immigrants will be given permanent status in ten years no matter what. Of course most observers expect the bill to spark lots of litigation — for example, there will be lawsuits claiming that immigrants should be eligible for federal benefits — and it’s entirely possible that litigation could tie up at least parts of the bill for years. So the catchall clause, still in the bill after the Hoeven-Corker amendment, guarantees that immigrants will win permanent status in the long run.

More later.