President Trump is hurtling toward a crossroads on immigration — his signature campaign issue and a key source of his law-and-order reputation — where each path before him comes with significant political risks.

Trump has temporarily placed the fates of roughly 800,000 undocumented immigrants brought to the United States as children in the hands of Congress, buying himself time and shunting responsibility.

Should Congress act, the president will have to choose whether to sign on to a legislative solution granting the “dreamers” legal status — or to let the Deferred Action for Childhood Arrivals program, known as DACA, expire, which would impede the ability of beneficiaries to find work and leave them vulnerable to deportation.

The choice cuts to the core of his presidency and could have long-term ramifications for the Republican Party.

“From a Republican Party point of view, this is a defining moment,” Sen. Lindsey O. Graham (R-S.C.), co-author of a bipartisan dreamers bill, told reporters Tuesday. As if addressing Trump, Graham added, “You have a chance to show the nation, as the president of all of us, where your heart’s at.”

Trump’s hard-line base, which demands purity and expects results, recoils at DACA as illegal amnesty and will look to him to veto any such legislation. But allies said Trump also is eager to prove that he has the “great heart” he has touted, and he is under pressure from his party’s establishment, the business community and many of his own advisers to find a way to let dreamers stay.

Trump’s 901-word statement on Tuesday explaining his decision zigzagged between those instincts. By the afternoon, when he sat down to a meeting at the White House with congressional leaders, Trump appeared to loosely come down on the side of the dreamers, saying he was confident lawmakers would achieve “the right solution.”

“I have a love for these people and hopefully now Congress will be able to help them and do it properly,” Trump said. “And I can tell you, speaking to members of Congress, they want to be able to do something and do it right. And really, we have no choice.”

On Tuesday night, Trump tweeted that he wanted to “legalize DACA,” another call to action that further muddled where the administration stood and what it would do.

“Congress now has 6 months to legalize DACA (something the Obama Administration was unable to do),” Trump wrote. “If they can’t, I will revisit the issue!”

Trump’s tone sharply contrasted with the harsher approach taken by Attorney General Jeff Sessions hours earlier at a news conference where he did not take questions. The difference highlighted the murkiness of the administration’s position.

“We cannot admit everyone who would like to come here,” Sessions told reporters. “It’s just that simple.”

Sessions’s view was echoed Tuesday throughout the conservative media universe.

Breitbart, the website managed by former White House chief strategist Stephen K. Bannon, published a story with the headline, “14 Things the [Mainstream Media] Won’t Tell You About DACA.”

On one of Trump’s favorite television programs, “Fox & Friends,” radio host and commentator Laura Ingraham, who has been friendly with the president for years, dismissed news coverage of DACA recipients as “sob stories.”

“I think there were a lot of folks who listen to my show, who turned out at these rallies for Donald Trump, who really loved his ‘America first’ message,” Ingraham said. “There are ways to be compassionate to people short of giving them work permits and federal benefits.”

Some Trump allies said they understood the president’s handling of DACA but did not echo him on every aspect of the issue.

“We have to recognize there are going to be two negative consequences of that action,” Sen. Tom Cotton (R-Ark.) said on conservative talk-radio host Hugh Hewitt’s program. “One, we create a new opportunity for citizenship through chain migration for their parents, the very people who violated the law by bringing them here as children in the first place. And two, we encourage other people around the world to bring their children here illegally.”

Trump wrestled with the DACA issue for months and into this past weekend, aides said. The decision to phase it out but allow a six-month delay to give Congress time to act underscores the president’s internal paralysis.

Trump in effect decided not to be the one who decides — at least for now.

The president’s punt created chaos at the other end of Pennsylvania Avenue, where it now falls to congressional Republicans to navigate a thicket of political interests and charged emotions amid a busy September as they try to keep the party’s base from revolting and still appeal to Hispanic voters.

Because of Trump’s lack of clarity, leaders of each wing of the GOP and Democrats are jockeying to shape the way DACA is addressed in the coming weeks. Deals are already being floated by figures who see the current vacuum as a useful opening to attach DACA to other priorities that have been lingering on Capitol Hill, such as extending the federal borrowing limit.

The White House has signaled that it would prefer Congress address the dreamers as part of a broader immigration package — one that could help Trump fulfill a major campaign promise by including funding for construction of a wall at the U.S.-Mexico border.

“We can’t take just a one-piece fix; we’ve got to do an overall immigration reform,” White House press secretary Sarah Huckabee Sanders said Tuesday.

Thomas M. Davis, a former Republican congressman from Virginia, said: "It's a great opportunity for this Congress and for Republicans to come together. It's an opportunity for Trump to say, 'Okay, I'll give you DACA, but I need my wall.' This is how deals can happen. Immigration reform was dead for years, and this reopens the conversation."

On the right, there were glimmers of potential for that type of agreement. Commentator Rush Limbaugh, whose syndicated talk-radio show is popular with many of Trump’s most fervent supporters, has proposed a similar compromise: Keep the dreamers and build the wall.

"Nobody wants to kick a bunch of kids out of the country, right?" Limbaugh said Tuesday on his program. "I don't care if they're budding little Al Capones. People just don't want to do it. . . . There needs to be a price, and it would be a great thing, couple this, say, with building the wall. I mean, you do all-in on border enforcement."

The timeline for congressional action is unclear, but top Republicans said addressing DACA could be fodder for legislative negotiations on other fronts.

“I think there may be a deal to be had,” Sen. John Cornyn of Texas, the Senate’s No. 2 Republican, told reporters when asked about DACA and border security.

Congressional observers said House and Senate leaders, who for years have taken more centrist positions on immigration than Trump, may want to handle the DACA issue sooner rather than later and well ahead of the 2018 midterm elections.

“This is one additional, very large agenda item, along with the debt ceiling, Harvey, tax reform, health care and all the spending bills,” David Winston, a veteran pollster who works with House Republicans, said. “It makes things so much more complicated, but I think you’ll see steps taken pretty quickly to begin this process. There’s a general consensus, although not a unanimous consensus.”

Kelsey Snell contributed to this report.