When Atty. Gen. Jeff Sessions announced the cancellation of the Deferred Action for Childhood Arrivals program this week, he said that President Trump would give Congress time to legalize the 800,000 undocumented immigrants known as “Dreamers.” Sessions also mentioned that he has “worked closely with many members of Congress, including in the introduction of the RAISE Act,” referring to the Senate bill that, if passed, would slash legal immigration in half.

The DACA announcement came two days after Sen. Tom Cotton of Arkansas, a cosponsor of the RAISE Act, told the Washington Examiner that Republicans should “find a way” to give Dreamers legal status, “but we also have to mitigate the inevitable consequences of that action.”

To immigration policy wonks, the message is clear: The White House is open to legalizing Dreamers, but only in exchange for concessions such as the RAISE Act.

It appears likely, in other words, that Republicans will attempt to use the fate of DACA recipients as leverage for comprehensive reform — a bringing-to-life of Trump’s entire immigration platform, which calls for the border wall and legislation similar to the RAISE Act, as well as mandatory participation in E‑Verify, the electronic employment eligibility verification system.

Those three measures happen to be the key components of a wish list published by the Center for Immigration Studies, a nativist think tank cited by Sessions and the White House policy advisor Stephen Miller. The CIS has explicitly endorsed a grand bargain in which amnesty is granted to Dreamers in exchange for the policies on the wish list.

But Congress isn’t likely to pass this kind of comprehensive deal. The policies are certain to be ineffective and expensive. What’s more, almost nobody would support such a package — not the Dreamers, not pro-immigration Americans, not even Trump’s base.

For starters, the proposed amnesty is puny. Dreamers make up about 7% of the estimated 11 million illegal immigrants who are currently in the country. Although Dreamers would be spared, a comprehensive deal would still leave a vast population of immigrants vulnerable to deportation.

Trump’s border wall promises to be a big-government boondoggle. According to Department of Homeland Security estimates, the wall will cost at least $17.3 million per mile to build and more than $21 billion overall, come with enormous annual maintenance costs and require so much private property from Texas ranchers that Trump’s budget sought 20 additional Department of Justice lawyers to ramp up eminent domain cases.

Furthermore, the wall won’t even work. Illegal border crossings are at a 46-year low. The majority of new illegal immigrants enter legally and overstay their visas. A wall can’t keep out overstays.

Full implementation of E‑Verify, which crosschecks information provided by job applicants with federal databases, would also be wasteful. A few states — Alabama, Arizona, Mississippi and South Carolina — already require that employers use E‑Verify, and the results have been abysmal. Businesses in these states ignore the mandate for about half of new hires. When the system is used, E‑Verify erroneously flags .3% of legal workers as illegal. At that rate, if applied nationally, the system would misidentify 420,000 legal workers as illegal.

Passing the RAISE Act would arguably be the costliest demand of a comprehensive deal. In cutting legal immigration in half, the bill would reduce the number of high-skilled immigrants allowed into the U.S. by around 100,000 per year. A year after it is passed, the act would force at least 500,000 skilled H‑1B workers to leave, taking their productivity with them.

Shrinking the workforce is not an effective way to grow wages for Americans. According to two widely cited studies, native-born Americans do not face much wage competition with immigrants. What’s more, according to my research, the RAISE Act would increase deficits by about $2.3 trillion over the next 75 years. The last time Congress cut legal migration to raise American wages, in 1964, the result was slower wage growth for low-skilled workers as employers mechanized in response.

There simply isn’t enough support for the reforms Trump wants. Only 37% of Americans want a border wall, E‑Verify (when costs are introduced) and drastic cuts in legal immigration, according to polls by Rasmussen, Reason-Rupe and Gallup, respectively.

Not to mention that Trump’s base doesn’t want amnesty for Dreamers. Many of them believe they were burned by President Reagan’s 1986 reform. That bill legalized about 3 million unlawful immigrants, but, as Mark Krikorian recently put it in the National Review, “the enforcement part of that bargain was vaporware, an airy promise that disappeared the moment the amnesty was completed.” Trump’s base will not accept a deal that repeats the “betrayal of ‘86.” They want deportations — period.

Even the supposed beneficiaries of such a bargain, the Dreamers, aren’t likely to support a deal that leaves their parents vulnerable to deportation and, if it includes the RAISE Act, would make it impossible for their parents to ever earn a green card.

Amnesty for Dreamers will fail if it is tied to the border wall, E‑Verify and the RAISE Act. That’s just as well, since the costs of such wrongheaded policies would far outweigh any benefits.