The House voted 230 to 195, mostly down party lines late Tuesday night to approve a $4.5 billion measure to send humanitarian relief to the southern border, addressing concerns about conditions of detention centers where migrant children are being held.
But before any migrants realize the benefits of the package, Republicans and President Trump must also act -- and so far the road ahead seems bumpy.
The White House has vowed to veto this version, and the Senate must pass a bill next -- whether it’s their version or the House’s -- before the president can sign anything into law.
Three Republicans voted in favor of the bill, and just four Democrats opposed the vote -- they were all freshmen Democrats, and arguably the highest profile freshmen from the 116th Congress: Reps. Alexandria Ocasio-Cortez, Ilhan Omar, Rashida Tlaib and Ayanna Pressley. All four said earlier in the week they would vote against the bill due to its funding of Immigration and Customs (ICE), which they have called for to be abolished.
Crossing the aisle to vote in favor were Republican moderate Reps. Mike Fitzpatrick, of Pennsylvania, Will Hurd, of Texas, and Chris Smith, of New Jersey.
The House goes on recess for 11 days on Thursday afternoon, so time is running short on lawmakers hoping for a bipartisan compromise.
The Senate could vote as soon as Wednesday on its own version, but identical legislation must pass both chambers before the president can sign a bill into law.
The House vote comes as the acting head of U.S. Customs and Border Protection, has told employees he is resigning from the agency and CBP officials, speaking on condition of anonymity, on Tuesday denied the allegations of mistreatment of children at the centers but said an internal investigation was underway.
"When we go to the floor, you will see our bill," Pelosi, D-Calif., told ABC News. "It’s for the children, the children, the children. It’s about lifting them up in a way that takes them beyond what we do today. This is a very strong step for us, a very strong first step for us for the children. It’s very exciting."
President Donald Trump expressed optimism that lawmakers would meet his $4.5 billion request for humanitarian assistance, even though the White House has signaled he would veto the House Democrats' version.
"Hopefully we're getting funding today. It's a humane bill. It's about humanity, helping children," Trump told reporters in the Oval Office Tuesday afternoon. "Mexico is doing much more for us than the Democrats and Congress. So it's a real simple thing to do. They just refuse to do it. I think we should probably be successful with humanitarian aid. It's going to have a big impact."
Pelosi has had to deal with Ocasio-Cortez and some other Democrats who were opposing the bill, wanting more specific language mandating how children should be treated and more restrictions on how the Trump administration can use the money to implement its immigration policies.
Early Tuesday morning, the White House issued a veto threat asserting the House legislation "contains a number of problematic policy provisions that would hinder the Administration’s efforts to enforce our immigration laws and protect children."
"The House majority has put forward a partisan bill that underfunds necessary accounts and seeks to take advantage of the current crisis by inserting policy provisions that would make our country less safe," a White House statement noted. "By opposing detention beds—where illegal migrants are placed pending their removal—Democrat lawmakers are declaring their belief that illegal immigrants, including those who skip court hearings or commit additional crimes, should be allowed to remain in our country indefinitely."
The Senate could vote on its own version of a border supplemental Tuesday, increasing pressure on Democrats to successfully clear their version, which has created some divisions within the Democratic Caucus, putting its passage in jeopardy.
"The Senate has a good bill. Our bill is much better. But if we are going to prevail we have to have a good, strong vote. You can find fault with any bill that comes down the pike, but we must respect the bill for what is does rather criticize it for what it does not," Pelosi told her caucus during a meeting Tuesday morning, according to a senior aide in the room. "A vote against this bill is a vote for Donald Trump and his inhumane, outside-the-circle of civilized attitude toward the children."
Monday night, Ocasio-Cortez, the New York freshman, and other Democrats dissatisfied with the bill huddled in Pelosi’s office, deliberating over plans to put their version of the $4.5 billion border aid package on the floor Tuesday.
Ocasio-Cortez expressed frustration that Republicans aren’t facing greater pressure and criticism over conditions at the detention centers, vowing to oppose the measure brought forward by party leaders.
"I will not fund another dime to allow ICE to continue its manipulative tactics," she said.
Monday night, Pelosi expressed a desire to further enhance protections for children in the bill, leaving Democrats scrambling to incorporate the proposals in an amendment ahead of a vote Tuesday.
After speaking to Pelosi on Friday night, Trump delayed mass deportation raids for two weeks, pressuring Congress to pass an immigration bill.
Democrats concede a comprehensive immigration bill is not possible to craft before Trump’s deadline, and Pelosi said the bill that came to a vote on Tuesday "isn’t an immigration bill."
"It’s not an immigration bill. It’s an appropriations bill to meet the needs of our children so we can remove the needs that they have but also the shame that we should have that they don’t have diapers and toothbrushes and the care," she said. "I said to the members, we have to have a country where every child knows that they are in their parents’ arms. Literally or figuratively. We are the arms of these children in terms of this appropriation is concerned. We want them to feel that comfort.
"I’m very proud of our members," Pelosi said. "So much work has gone into it to have a back and forth so we have the strongest possible bill. But again, it’s not an immigration bill. It is an appropriations bill to meet the needs of the children."
ABC News' Ben Siegel contributed to this report