(CNN) President Donald Trump has tasked chief of staff John Kelly with shepherding his immigration proposals through Congress, several administration officials and others familiar with the situation say, in the hopes the retired Marine general can help him fulfill core campaign promises ahead of the 2018 midterm elections.

Assigning the chief of staff to such a specific policy initiative is rare, given the top aide's duties in running White House operations and overseeing disparate factions in the West Wing. But Trump hopes Kelly can lend authority to his immigration push without sacrificing the hard-line positions he's advocated. Kelly served as Trump's first homeland security secretary and spearheaded the immigration efforts from that post in the first months of the administration.

The push will continue Tuesday when lawmakers meet at the White House to discuss the next steps on immigration reform. Kelly will helm the meeting alongside Trump, people familiar with it said, though the prospects of striking an agreement appeared slim.

Other administration officials participating in the session include Kirstjen Nielsen, the homeland security secretary; Stephen Miller, senior adviser for policy; and Marc Short, the White House legislative affairs director.

Lawmakers and the White House hope to strike an agreement on the legal status of some young undocumented immigrants. Trump warned over the weekend, however, that any plan to help the recipients of the Deferred Action for Childhood Arrivals program would need to include authorization of a border wall, his chief campaign promise.

Democrats have resisted those demands, making the chances of any agreement slim. The DACA issue has proven one of the stickiest as lawmakers work to negotiate a spending deal that would avoid a government shutdown.

Democrats including Sens. Dick Durbin of Illinois, Dianne Feinstein of California, Heidi Heitkamp of North Dakota, Bob Menendez of New Jersey and Jon Tester of Montana will attend Tuesday's meeting, the White House said. Durbin, a lead negotiator on immigration, has rejected the White House's proposals out of hand.

Trump, meanwhile, has insisted that his wall be built and hopes Kelly can help reach an agreement with Democrats that will allow him to fulfill his campaign promise.

An administration official said Monday that Kelly has maintained a good relationship with Sen. Chuck Schumer of New York and Rep. Nancy Pelosi of California despite Trump's criticism of the congressional Democratic leaders. Officials said Trump viewed his chief of staff as the best hope of striking some type of deal.

That's left Miller, the policy adviser, to play second fiddle, officials said. Miller has been a staunch and outspoken proponent of limiting immigration to the United States, and is viewed as the White House's guiding voice on the matter.

Kelly is "more of an adult," one person familiar with the situation said, and Trump believes that with him in charge there's a better chance of getting something done. Another person said Kelly respects Miller but is the clear person in charge over him, with no question of the line of authority.

Two Democratic aides involved in the process said that while they were under the impression Kelly was playing a more robust role in the process, they didn't view him as any kind of moderating force when it came to the policy.

"None of our experiences with him at DHS would make us think that's a better deal on the policy," one aide said of the idea of dealing with Kelly instead of Miller. But the aide acknowledged that Democratic negotiators have a more extensive working relationship with Kelly -- compared to a nonexistent one with Miller.