President Donald Trump is reportedly less than pleased with the omnibus spending dealCongress is voting on Thursday to fund the government through the end of September. And he has every right to be frustrated.

The omnibus bill gives the president very little of what he asked for on immigration enforcement — arguably his top domestic policy priority. Not only does it not give him the billions of dollars the White House wants for a “big, beautiful wall,” or contain restrictions on funding for “sanctuary cities,” but Congress is actually making an effort to rein in the Trump administration’s overspending on immigration detention instead of expanding it.

The president was reportedly threatening as late as Wednesday to veto the bill over these issues, though House Speaker Paul Ryan and Senate Majority Leader Mitch McConnell appear to have talked him down. But the spending deal makes clear that the White House’s current approach to immigration in Congress simply isn’t working. And that’s guaranteed to piss Trump off.

Congress is willing to fund border barriers — just not the ones Trump wants

Congress isn’t giving the president the $25 billion the White House says it will take to fulfill its plan to build several hundred miles of barriers along the US/Mexico border. But this bill is technically for the rest of the current fiscal year — the one that expires on September 30. And Congress is actually giving the administration $1.375 billion of the $1.6 billion it requested for border barriers last May, in its budget request for the current fiscal year — even if the omnibus bill insists on calling it “fencing” rather than a wall.

They’re appropriating $445 million for 25 miles of levee fencing in the Rio Grande Valley (and another $196 million for an unspecified amount of regular pedestrian fencing there); $251 million to replace 14 miles of existing secondary fencing in the San Diego sector; and $445 million to replace an unspecified amount more of pedestrian fencing. (If you’re curious about the difference between primary and secondary fencing, check out our border wall explainer.)

Speaker Paul Ryan and other Republicans have insisted that the bill funds the wall. As policy, they’re right — there’s no reason that President Trump couldn’t take credit for building a few dozen miles of fencing as “continuing to build the wall.”

But, crucially, the bill specifically prevents the Trump administration from using any of the new wall designs it commissioned and tested in California last year. All money has to be spent on “operationally effective designs deployed as of the date of the Consolidated Appropriations Act, 2017” — a bill Trump signed on May 5, 2017.

If President Trump cared less about his wall than about a wall, this wouldn’t be an issue. But everything we know about the president indicates that’s not the case, and that this is a blow to his ego — he reportedly upbraided congressional Republicans this week for not supporting it, claiming they “owed” him for his support for the tax bill and his nomination of Neil Gorsuch to the Supreme Court. The bullying tactics do not appear to have worked.

A strict admonishment to ICE to “live within its means” on immigration detention

In past spending fights, Trump’s (and Democrats’) fixation on the wall has kind of obscured things that have an objectively bigger impact on immigration policy — namely, the amount of money being given to Immigration and Customs Enforcement (ICE) to expand interior immigration enforcement and deportations by hiring more agents and expanding immigration detention.

This is an area where congressional Republicans might be expected to fight harder for the administration than a mostly symbolic wall. But they’re not — or, at least, they weren’t willing to risk a shutdown over it.

Trump wanted 1,000 new ICE agents; he’s getting barely 100, and none of them are the field agents responsible for arresting unauthorized immigrants. (Instead, ICE is getting more staff for investigations and mission support.)

And when it comes to immigration detention, Congress isn’t just refusing to give the White House the 20 percent increase in detention Trump asked for — it’s rebuking ICE for overspending and expecting Congress to bail it out.

Under the last budget, ICE was given enough money to keep 39,324 immigrants in detention at any given time. They’ve been overshooting that cap by over 1,000 immigrants a day. To cover the increased costs, they’ve been shifting money from other areas — something the administration is allowed to do up to a certain point — and asking for supplemental funding from Congress as, essentially, a reimbursement.

As the explanatory text for the omnibus shows, Congress is not pleased:

Between October 1, 2017, and the date of enactment of this Act, when the Department was operating under the terms of a continuing resolution (CR), ICE exceeded its annualized rate of funding for Custody Operations. During the period of any future CR, including any CR for fiscal year 2019, ICE is directed to manage its resources in a way that ensures it will not exceed the annualized rate of funding for the fiscal year. ICE is directed to update the Committees weekly on its rate of operations for Custody Operations to demonstrate how the agency is living within its means.

The omnibus gives ICE money to keep an average of 40,520 immigrants in detention on any given day. In order to meet that target (and “live within their means”), they’re going to have to start detaining fewer immigrants than that by the end of the fiscal year.

Compared to what Congress authorized last year, this is still an expansion of detention. But the Trump administration didn’t actually take that authorization seriously. And instead of responding by giving ICE the money it needs to keep holding more immigrants, Congress is reminding ICE who holds the purse strings.

Trump’s real problem on immigration in Congress isn’t Democrats. It’s Republicans.

To a certain extent, this probably reflects Democrats’ renewed attention to limiting funding for Trump’s immigration agenda, especially in the absence of passing any bills that would legalize any unauthorized immigrants. But the White House’s real problem isn’t that Democrats are using their leverage to restrict immigration enforcement money — it’s that congressional Republican leadership isn’t willing to put up a fight (and risk a shutdown) to give the White House what it wants.

The president has hinted in the past that he thinks the border wall is an important enough priority to force a government shutdown. He’s flirted with vetoing bills — including this one — for not including it. As Vox’s Tara Golshan has reported, the White House made a belated effort to insist on using the omnibus to target sanctuary cities. None of those threats have gone anywhere with congressional leadership.

Furthermore, the way the Trump administration is carrying out immigration enforcement right now — its “detain now, fund later” approach — has given congressional Republicans little appetite to insist on keeping detention levels where they are, much less expanding them.

Partly, this is because President Trump isn’t spending much capital or attention on the heart of his immigration enforcement operation, relying on the Department of Homeland Security (and Attorney General Jeff Sessions) to do it for him. But partly, it appears to be because a lot of Republicans in Congress don’t feel the White House is negotiating with them in good faith on immigration.

After the fight over the Deferred Action for Childhood Arrivals (DACA) program this winter, during which Trump frequently claimed he wanted to make a deal and then rejected any bipartisan deal that came to him, congressional Republicans don’t seem that interested in trying to guess what the president will actually sign.

That is, by all appearances, infuriating to Trump. But being furious at Congress doesn’t appear to be working. Maybe the White House needs to try something else.