The Trump administration has been active in changing immigration policy through the executive branch, but it’s turning its sights toward Congress.

President Donald Trump himself is already in demand-making mode: On Tuesday, he threatened a government shutdown at the end of September if he hasn’t gotten money for his border wall (which Congress was unwilling to give him in April).

But as big an ask as that might be, the White House’s expectations for Congress are actually much, much higher than that — much to Congress’s chagrin.

A new report by McClatchy’s Anita Kumar suggests several key Trump advisers, including Chief of Staff John Kelly, are hoping for a “grand bargain” on immigration.

The “grand bargain” would include the RAISE Act — the bill introduced by Sens. Tom Cotton (R-AR) and David Perdue (R-GA) in July with the White House’s blessing, which aims to cut legal permanent immigration to the US by half over the next decade, and which has barely any support in Congress as is. But that would only be the beginning.

It would also include a mandate for all employers to use the electronic E-Verify system to check the legal status of everyone they hire (which would theoretically make it all but impossible for unauthorized immigrants to work), and funding for a border wall and more detention facilities. In return, the 800,000 young unauthorized immigrants currently protected under the Deferred Action for Childhood Arrivals program would be allowed to apply for full legal status and ultimately citizenship.

This theory is divisive even within the White House — a faction of advisers including senior policy adviser Stephen Miller, who formerly worked for immigration hawk Jeff Sessions, are strongly opposed to allowing any currently unauthorized immigrants to become legal. But the bigger problem isn’t Miller. It’s the fact that the Trump administration isn’t designing this bargain in a vacuum — it’s trying to change the terms of a debate in Congress that’s been quietly ongoing.

Several different factions in Congress have discrete aspects of immigration policy that they want to change — and they’ve been quietly laying down markers about what changes they’d like to see, in the hopes of assembling a compromise from some or all of the existing proposals if and when Congress really is forced to act.

Slowly, the sides have been shaping up. Democrats (and a few Republicans) are worried that the Trump administration will strip legal protections from DACA recipients; if that happens, they’re ready to push for Congress to grant those immigrants full legal status instead. Various Republicans, meanwhile, have offered proposals to beef up various aspects of immigration enforcement — teeing up something for Congress to do in fall to pursue the president’s agenda, or to pair with one of the DACA legalization proposals, giving both Democrats and Republicans something they want that’s short of a “comprehensive” legalization bill or a comprehensive crackdown.

What the Trump White House wants, however, is a comprehensive crackdown paired with a much-less-than-comprehensive legalization bill. It’s way outside the goalposts that Congress has set so far — and way more favorable to the hardliners. And the process of getting it or anything like it through Congress would result in exactly the kind of comprehensive, free-for-all immigration debate that congressional leadership has been anxious to avoid — and that the White House can’t control.

Here are the existing factions — and the wild cards the White House is threatening to throw, intentionally or not, into the mix.

The “merit-based legal immigration” faction

What they want: There are plenty of Republicans who agree, in theory, with the Trump administration’s push to revamp the way the US selects immigrants to come into the US legally, so that preference goes to highly educated and “skilled” workers instead of family members of current US citizens and green card holders. But most of them want this to happen because they want to see more skilled immigrants come to the US — while the Trump administration wants the same number of skilled immigrants, and simply wants fewer unskilled immigrants and family members to come alongside them.

Who’s in it: How big this faction is really depends on how you define what it wants. Sens. Tom Cotton (R-AR) and David Perdue (R-GA) are two of the only members of Congress who support the RAISE Act as it is, but interest in some form of “merit-based immigration” is pretty widespread among Republicans, including Senate Majority Whip John Cornyn (R-TX) and House Immigration Subcommittee chair Raul Labrador (R-ID).

The US hands out a majority of green cards each year on the basis of family ties — spouses, children, parents, and (in rare cases) siblings of US citizens and permanent residents. Many Republicans have been arguing for years that that balance needs to shift in favor of immigrants selected on “merit” — which, in practice, tends to mean highly educated professionals, often in the sciences.

On its surface, the RAISE Act does just that. But it doesn’t actually expand the number of green cards available to skilled immigrants. It just cuts the number available to family members.

The point of past “merit-based” immigration proposals has usually been to allow more “high-skilled” immigrants to settle in the US, which the RAISE Act doesn’t provide for. And its deep cuts to the rest of the legal immigration system — capping refugees at 50,000 a year, eliminating the “diversity visa” program, and an 85 percent reduction in family-based immigration — may go too far even for people who think the current system lets too many “low-skilled” immigrants in.

The general attitude toward the RAISE Act in Congress appears to be, as Sen. Cornyn said about the bill when it came out, that it’s a “beginning, not the end,” of the conversation. If Congress is approaching the RAISE Act as a starting point for negotiations, it’s plausible the bill will change a great deal — at least enough to get some of the typical supporters of “merit-based” fixes to future immigration flows on board.

But it’s not clear whether the White House thinks that the RAISE Act is just an opening gambit.

When the bill was originally introduced, Mark Krikorian, who heads the foremost immigration-hawk think tank the Center for Immigration Studies, floated the idea that the RAISE Act could pass as-is by being paired with a way for current DACA recipients to get permanent legal status. That was before reports of the White House’s desire for a “grand bargain,” which would include immigration enforcement as well as cuts to legal immigration in exchange for the opportunity for 800,000 unauthorized immigrants to apply for legal status.

The “Deportation Force” faction

What they want: To maximize law enforcement power to go after unauthorized immigrants living in the United States — criminals or not.

Who’s leading it: Led by House Judiciary Chair Bob Goodlatte (R-VA), with the support of the Trump White House.

The core of President Trump’s immigration agenda has always been about the United States: going after unauthorized immigrants who are already living here, using the tools of law enforcement. Immigration hawks in Congress have been trying to pass bills along these lines for more than a decade, and now, they have the White House’s imprimatur. It’s just not clear whether that will be enough.

The only major immigration bill passed out of a congressional committee this year belongs to this genre. Called the Davis-Oliver Act in honor of two deputy sheriffs from California killed by unauthorized immigrants during a traffic stop in 2014. The bill would give state and local law enforcement officials around the US the power to enforce federal immigration law — specifically, to “investigate, identify, apprehend, arrest [and] detain” people they suspected of violating it. It wouldn’t require law enforcement officers to do that, a la Arizona’s 2010 law SB 1070, but it would allow them to.

The bill would also authorize the hiring of up to 12,500 ICE agents and allow all ICE agents to carry firearms; put more pressure on state and local governments to comply with federal requests to take immigrants into custody and bar “sanctuary cities” from federal law-enforcement grants; and make it possible to deport legal immigrants for being judged gang members, among a host of other provisions to expand enforcement.

Those backing the Davis-Oliver Act are looking for opportunities to deport unauthorized immigrants living in the US. This means they will hold firm on any bill that doesn’t sufficiently do this. If there’s going to be any movement on immigration, there will likely be clamor to add this to the mix.

The “build a smarter border” faction

What they want: A buildup of infrastructure, technology, and manpower on the US/Mexico border — but not, necessarily, a literal “wall.”

Who’s leading it: The key “influencers” here are House Homeland Security Committee chair Michael McCaul and Senate Majority Whip John Cornyn, both Republicans from Texas.

Most Republicans in Congress would be happy to vote for a bill that would “improve border security” — especially if it’s not too expensive. But few of them have strong opinions about just what such a bill ought to look like (and very few of them had any interest in siding with the Trump administration when it attempted to bully Congress into including funds for “the wall” in a government-funding bill this spring).

Right before the August recess, though, bills were introduced in both chambers by people who do know something about the issue: McCaul and Cornyn. And both of those bills could readily be teed up when Congress returns in the fall, to be passed on their own (unlikely in the Senate) or added as the “border” component of whatever immigration package Congress kludges together.

Both bills would give the Department of Homeland Security $15 billion to expand border security — using both “tactical infrastructure” (which may include physical barriers but doesn’t necessarily include a literal wall) and improved technology. They’d give DHS a lot of leeway to determine what’s actually needed. And they’d allow the government to hire thousands more Border Patrol agents and ports-of-entry agents, while waiving the current polygraph requirement for certain Border Patrol applicants (Border Patrol has a staffing shortage right now, and the fact that its polygraph test flunks a lot more applicants than polygraphs in other agencies appears to be part of the reason).

The Cornyn and McCaul bills are both fairly moderate. They’re the sort of thing that Democrats would have signed onto without a second thought 10 years ago. But in the current environment, Democrats aren’t interested in passing any immigration enforcement that isn’t paired with something to protect any of the unauthorized immigrants currently in the US. And many immigration hawks are uninterested in “just” passing a border bill, without also cracking down on immigration enforcement within the US.

The “protect the DREAMers” faction

What they want: Continued legal protection for the 800,000 or so unauthorized immigrants currently protected through the Deferred Action for Childhood Arrivals (DACA) program created by President Barack Obama in 2012.

Who’s in it: Democrats in both chambers; Sen. Lindsey Graham (R-SC); a block of moderate Republicans (most of them in swing districts) like Rep. Mike Coffman (R-CO); Sen. Jeff Flake (R-AZ) and Sen. Marco Rubio (R-FL) (both inactive)

Right now, this faction doesn’t really need to do anything: The DACA program remains in place, meaning that the immigrants it protects (who arrived in the US as children and are often referred to as “DREAMers”) are still protected from deportation and allowed to work legally.

But President Trump and his administration keep making noise about ending the program — and if they don’t make a move by September 5, a group of Republican state officials are threatening to get it blocked in court.

September 5 is, coincidentally, the same week Congress returns from August recess. And if Congress comes back to a Washington without DACA, a lot of members of Congress — not just Democrats, but many Republicans as well — are going to feel pressured to do something to protect immigrants who’ve grown up in the United States.

Until that happens, we won’t know just how many members are in this faction. Certain Republicans who support DACA and have supported immigration reform in the past are taking a “we’ll cross that bridge when we come to it” attitude. But others are already warning the administration that if it ends DACA, they’ll step into action. Indeed, in the weeks before August recess, two different bills got introduced to address the status of DACA recipients — in addition to the two that were introduced during previous DACA scares.

Some of the bills are more bipartisan than others; House Democrats’ American Hope Act is the broadest bill yet proposed to deal with the DREAMers, while the Recognizing America’s Children (RAC) Act from a group of moderate House Republicans places moderate restrictions on DREAMers before they’re allowed to get green cards. (In the center, and appropriately bipartisan, are the latest versions of the DREAM Act introduced in the House and Senate.) Fundamentally, though, the bills are pretty similar: All of them would allow people who currently have protections under DACA to apply for full legal status in the US and eventually be allowed to become American citizens.

The White House has already indicated that President Trump wouldn’t sign such a bill as a stand-alone. Most members of this faction, though, would privately admit that they’re willing to pair protections for the DREAMers with some immigration enforcement measures.

The question is just how far they’re willing to go.

It would be easy for Democrats to agree to give the Trump administration the $1.5 billion in border “wall” funding for the next fiscal year that it’s already asking for (enough to build less than 100 miles of fencing and levees) in exchange for legalizing 800,000 immigrants. But the other factions in play — all of them various groups of Republicans interested in expanding immigration enforcement and restrictions — don’t see that as anything close to a fair deal.

The White House wants a “grand bargain” — but Trump can’t actually control what’s in it

Before the Trump administration got involved, the markers being laid down by each faction for “what they would want Congress to pass on immigration” were fairly measured requests. Legalizing DACA recipients may be controversial, but it would certainly be easier to swallow than legalizing all 11 million unauthorized immigrants. The Davis-Oliver Act would be a big step up for immigration enforcement, but not quite as aggressive as making the E-Verify system (which checks the legal status of workers and applicants) mandatory for all employers in the US.

The RAISE Act is a broader transformation of immigration policy (in the context of past immigration debates, and what members of Congress care enough about to speak out on) than providing a path to citizenship for all unauthorized immigrants, or mandatory E-Verify. If the other factions are currently operating at a 5 in terms of what they’re willing to ask for, the RAISE Act immediately went to 10.

And if the McClatchy report is accurate, the White House thinks they can get not only something like the RAISE Act, but mandatory E-Verify as well, into their grand bargain. In exchange for getting a 5 on the immigrant-legalization scale, they’d be asking for a 10 on the cutting-legal-immigration scale plus a 10 on the interior-enforcement scale.

The reason that the factions in Congress have been playing small ball, so far, is that they’ve been sticking to bills they think would get a majority of support in Congress without substantial amendments — as long as they were part of a bigger package. Democrats see the negotiations over DACA as “what enforcement bill will we accept with this,” not “how much are we willing to further restrict legalization for DACA recipients.” Some Republicans, meanwhile, see the border and interior enforcement bills as hand in hand.

The RAISE Act doesn’t fit that model. Its fiercest proponents may think it ought to pass as is, alongside some form of legalization for DACA recipients, but everyone else sees it as the start of a conversation — in other words, an opening play in a negotiation that would result in a more moderate RAISE Act.

But other factions can also play that game. If the DACA caucus followed the RAISE Act’s lead, they could propose a bill that allowed all 11 million unauthorized immigrants to become US citizens. If the deportation-force caucus did, they could propose mandatory E-Verify and making unauthorized presence a criminal offense.

Those proposals would have to be negotiated, and moderated, to get enough votes — rather than quickly assembling a passage of moderate-to-moderately-serious bills and passing them with minimal debate.

And then there are the people who aren’t really speaking out yet at all: the members who want more low-skilled immigration, in general or for particular industries in their states. If a large immigration package is being discussed — especially one that addresses “future flows” of legal immigrants — they have every reason to expect that their requests should be considered as part of it.

In other words, it would cause exactly the policy clusterfuck that Republican leadership so desperately wants to avoid. And the stakes would be much higher for every immigrant in the US — and everyone who might ever want to bring or hire one.