Slowly, drip by drip, a congressional fight over immigration appears to be brewing.

After a week of policy losses on health care, President Donald Trump stood alongside Sens. Tom Cotton (R-AR) and David Perdue (R-GA) to introduce legislation Wednesday that takes aim at the nation’s immigration system.

It was a clear sign the White House has been itching to bring immigration front and center.

“This is what President Trump campaigned on,” White House adviser Stephen Miller, who helped craft this bill, said at the daily press briefing Wednesday. “It's pro-American immigration reform that the American people want, that the American people deserve, and that puts the needs of the working class ahead of the investor class.”

The Cotton-Perdue plan would cut the number of legal immigrants entering the United States in half by 2027, cap the number of refugees, and eliminate the “diversity visa lottery,” a program that grants green cards to regions that do not have as many immigrants in the United States.

On its own, the bill — the Reforming American Immigration for Strong Employment (RAISE) Act — will almost certainly fail to garner 60 votes to pass the Senate. But it’s yet another signal that there is a contingent of Republicans in Congress open to an immigration fight on Capitol Hill.

The RAISE Act is among a handful of Republican proposals introduced in recent months aimed at actualizing Trump’s far-right immigration agenda. In the House, several proposals have surfaced that would allow local law enforcement officers to enforce federal immigration laws, cut off funding to sanctuary cities, and overhaul the asylum system in the United States. And the White House’s most vocal critics of legal and illegal immigration, Miller and White House chief strategist Steve Bannon, have had a heavy hand in these proposals.

Only a few months ago, there seemed to be widespread consensus among congressional Republicans that immigration wasn’t a top priority for this Congress — many told Vox they were waiting for action from Trump.

Now, with yet another spending package on the horizon that could contain money for Trump’s border wall and a looming deadline over the fate of unauthorized immigrants who qualify for the Obama-era deferred action initiative in September, a fight over immigration policy might be unavoidable. These more extreme proposals could be signs of how the immigration hawks will organize around negotiations.

The far-right immigration playbook has been popping up more and more

There’s no question that the White House has a long to-do list on immigration. In early May, a photograph of Bannon revealed a whiteboard in the West Wing with at least 18 immigration-related bullet points (text cut off by photo is filled in with italics below):

Cancel all federal funding to sanctuary cities

Build the border wall and eventually make Mexico (pay for it)

Sunset our visa laws so that Congress is forced (...) revise and revisit them

Finally complete the biometric entry-exit visa tra(cking system)

Propose Passage of Davis-Oliver Bill

Immediately terminate Obama’s “two illegal e(xecutive orders”?)

It appears as though some Republicans in Congress are beginning to follow through on some of these priorities. The Davis-Oliver Act — proposed by Rep. Raúl Labrador (R-ID) mirroring something previously proposed by Attorney General Jeff Sessions — allows local law enforcement to enforce federal immigration law, calls for an additional 10,000 immigration officers, and makes all immigrants in criminal street gangs deportable.

The bill has yet to see a floor vote in the House, and is widely considered to be one of the most aggressive Trumpian immigration reforms.

As is the RAISE Act — Cotton and Perdue’s bill — which pushes for what Trump calls a “merit-based” immigration system, which would “favor applicants who can speak English, physically support themselves and their families, and demonstrate skills that will contribute to our economy,” Trump said at a press conference Wednesday.

But as Vox’s Dara Lind explained, “reforming the immigration system to be more ‘merit-based’ is predicated on the idea that some of these slots are going to the wrong immigrants — immigrants who don’t have as much to give the US as the US has to give them.”

Cotton has been upfront about this. His spokesperson highlighted the need to prioritize highly skilled immigrants:

Cotton spox; Only 1 in 15 immigrants come here because of their skills. And we don’t prioritize ultra high-skilled immigrants. — Chad Pergram (@ChadPergram) August 2, 2017

These are ideas put forward by Congress’s immigration hawks and are almost certainly going to fail in a full vote. But more importantly, they are strong signals that there are Republicans willing to go to the mat over Trump’s far-right immigration agenda.

And eventually, if Trump wishes, there will be immigration issues — like border security or the status of DREAMers — that Congress will be forced to address. These proposals simply set a stake.

An immigration showdown is looking more and more likely

Already, reporters and political aides have been musing about the outcome of a vote on a proposal like the RAISE Act: Everyone knows it’s unlikely to pass.

Not only will it fail to get the Democratic votes it would need to reach the threshold in the Senate, but moderate Republicans are likely to balk at it as well.

When Cotton and Perdue introduced their proposal in February, it received some poor reviews from Republicans who are more dovish on immigration. Sen. John McCain told reporters he was “not interested” in it. Sen. Jeff Flake (R-AZ) argued in favor of the low-wage “guest worker” programs that this proposal aims to curb. Sen. Lindsey Graham (R-SC) said the United States needed to “replenish our workforce.”

Unquestionably, much like on health care reform, the Republican conference is sharply divided on immigration reform — making it easy to write off many of these proposals as messaging bills from conservative hawkish members.

But there are some immigration issues Trump can use to force Congress into action on his pet issue. He can fight for more border security money, or he can end the Obama-era Deferred Action for Childhood Arrivals program, which allowed young unauthorized immigrants to work legally and protected them from deportation — a possibility that congressional Democrats have been warning constituents about after a meeting with former Department of Homeland Security Secretary John Kelly.

And as Lind explained, if something like that happens, and suddenly Democrats and moderate Republicans are pushed into the business of immigration reform, it becomes a question of what conservatives will demand in return:

It’s plausible that some conservatives — or even some White House officials, like Steve Bannon or Stephen Miller — will be pushing for permanent policy changes to the immigration system as a condition for allowing those 780,000 immigrants to stay without fear. They might demand that the bills passed by the House last month, which mandated five-year prison sentences for illegal reentry into the US and stripped some federal funding from “sanctuary cities” that didn’t agree to hold immigrants for pickup by federal agents, be added to any compromise.

It comes down to how far Trump is willing to go, and how Congress will scramble to fill in the cracks.