President Trump made his first public case Tuesday in support of providing legal residency to younger undocumented immigrants known as "dreamers," hoping his State of the Union address to Congress would build support for a politically risky immigration plan.

Trump's prime-time speech was a chance to push for an immigration overhaul in sober language, without vulgar deprecations of poorer countries or the fervor of his wall-building rally chants. It also represented a potentially legacy-defining moment for a president who campaigned on a hard-line immigration agenda but is now trying to sell a White House compromise on broad legislation that eluded his recent predecessors.

Under mounting pressure from his base to build a border wall, Trump made an impassioned plea for a plan, released by the White House last week, that represents his best shot — but one that already has drawn objections from most Democrats and some conservative Republicans. Liberal groups have called Trump's proposal an attempt to use dreamers as "ransom" for a "white-supremacist" agenda, while hard-line conservatives have denounced Trump's support of "amnesty" for dreamers.

"My administration has met extensively with both Democrats and Republicans to craft a bipartisan approach to immigration reform," Trump said, urging lawmakers to support his demands for sharp cuts to legal immigration programs and $25 billion to expand the border wall.

"Based on these discussions, we presented the Congress with a detailed proposal that should be supported by both parties as a fair compromise — one where nobody gets everything they want, but where our country gets the critical reforms it needs."

Trump used his speech to highlight the threats posed to public safety by dangerous immigrants, honoring the families of two teenage girls killed on Long Island by the El Salvador-based MS-13 gang. Asking the slain girls' families to stand for applause, Trump told them "320 million hearts are breaking for you" and "we love you."

For a president whose critics cast him as callous to the plight of immigrant families, it was an emotional high point in the speech, and television cameras at one point turned to Homeland Security Secretary Kirstjen Nielsen, who appeared to be holding back tears.

Trump also introduced Celestino "CJ" Martinez, an Immigration and Customs Enforcement special agent who led New York-area investigations into the gang, whose brutal crimes the administration points to as further evidence of the need to eliminate "loopholes" that Trump said allow dangerous criminals to enter the country.

Trump then laid out the four pillars of his proposal, starting with a path to citizenship for up to 1.8 million dreamers, undocumented immigrants brought to the country as children.

"That covers almost three times more people than the previous administration covered," Trump said, calling the offer generous. "Under our plan, those who meet education and work requirements and show good moral character will be able to become full citizens of the United States over a 12-year period."

In the fall, Trump terminated the Obama-era Deferred Action for Childhood Arrivals program that provided work permits to 690,000 dreamers. The bulk of their permits could begin to expire March 5 unless Congress provides a legislative solution.

At least 22 dreamers were in the House chamber as guests of lawmakers, all of them Democrats except for Rep. Carlos Curbelo (R-Fla.), who invited a Miami tennis instructor.

Trump laid out three other tenets of his immigration overhaul: tougher border security anchored by a wall; an end to the diversity visa lottery; and an end to the family reunification visa categories, which Trump referred to as "chain migration."

"Under the current broken system, a single immigrant can bring in virtually unlimited numbers of distant relatives," he said, bringing jeers from the Democrats' side of the room. "Under our plan, we focus on the immediate family by limiting sponsorships to spouses and minor children."

U.S. immigration laws do not allow citizens to sponsor distant relatives in foreign countries, as Trump claimed. But visa categories that allow citizens to bring siblings and adult children are prime targets for immigration restrictionists.

Democrats have pushed back hardest against these proposals, especially provisions that — as Trump proposed Tuesday — would bar American citizens from helping their parents get green cards.

"These four pillars represent a down-the-middle compromise, and one that will create a safe, modern and lawful immigration system," Trump said.

The dramatic setting in the ornate Capitol illustrated the heightened stakes surrounding the immigration debate and marked the opening of the White House's bid to use the next week to win leverage in the negotiations. Lawmakers face a Feb. 8 deadline for a must-pass spending bill to keep the government open, but some Democrats and a few Republicans have said they will not support a long-term deal that does not include an immigration agreement.

White House aides said they hoped Senate Majority Leader Mitch McConnell (R-Ky.) would bring a bill based on Trump's proposal to the floor for a vote next week. But McConnell, who called Trump's plan a constructive step forward, has made no promises.

The president's proposal would also add hundreds of additional immigration agents and judges to increase and speed up deportations.

If enacted, Trump's plan could slash legal immigration levels by up to 44 percent, according to an analysis released this week by the libertarian Cato Institute.

But it remains to be seen whether hard-liners in his party will get behind it, as many have bristled at any proposal to give DACA recipients — let alone 1.8 million undocumented immigrants — a path to citizenship. Rep. Mark Meadows (R-N.C.), head of the conservative Freedom Caucus, said that Trump's plan would need major changes before gaining support on the political right.

"How do we perfect that to make sure that there's not a special pathway to citizenship?" Meadows told reporters of Trump's proposal to legalize dreamers.

Senate Democrats forced a three-day partial government shutdown earlier this month over the immigration issue. With a new deadline fast approaching, some Hispanic lawmakers complained to Senate Minority Leader Charles E. Schumer (D-N.Y.) over his willingness to negotiate with Trump over funding for the border wall. Schumer has since rescinded his offer.

Trump aides framed his first official State of the Union address as a chance for the often divisive president to reach out beyond his conservative base and speak to a broader audience across the country.

Polls show that the majority of Americans support measures to protect "dreamers" from deportation and that they are skeptical of Trump's plans for a costly border wall.

Before taking office, Trump said he would jettison millions of "bad hombres" from the country. His administration has fallen far short of that goal, but not for lack of effort. Arrests by ICE officers surged nearly 40 percent last year, but a drop in illegal border crossings left the government with a smaller pool of people to deport.

But the chilling effect of Trump's tough talk at the border appears to have begun to wear off. Though illegal crossings dropped to their lowest levels on record in the first four months of his presidency, they have ticked upward ever since.

U.S. agents last month made more than 40,000 arrests along the border with Mexico, the highest total since Trump took office.

Ed O'Keefe contributed to this report.