The US House of Representatives passed a bill that would give permanent citizenship to 2.5 million undocumented immigrants on Tuesday, on a final vote of 237-187. Like most of the rest of the Democratic agenda, it’s likely headed to Senate Majority Leader Mitch McConnell’s dustbin.

House Democrats’ Dream and Promise Act, introduced in March, is an attempt to give a pathway to citizenship to two major groups of immigrants whose legal status President Donald Trump has repeatedly threatened: unauthorized immigrants who were brought to the US as children (known as DREAMers) and immigrants with temporary humanitarians protections.

“Dreamers and those with TPS (Temporary Protected Status) and DED (Deferred Enforced Departure) status are contributing to our country and to our economy, and deserve to have certainty that they will be able to stay with their families in the place they call home,” House Majority Leader Steny Hoyer wrote in a Dear Colleague letter to the Democratic caucus this week.

Even though a number of Republicans support the Deferred Action for Childhood Arrivals program that protects DREAMers currently, the broad nature of this bill will make it a tough sell in the US Senate, especially with the 2020 election looming. Immigration has been the basis of many of the worst fights between Trump and Congress, giving McConnell little incentive to bring a bill up in the Senate.

And even though Democrats have made creating a pathway to citizenship for DACA and TPS recipients one of their top priorities, the much harder work of comprehensive immigration reform is yet to come. Opposing Trump is the easy part, and the president’s hardline policies have had a uniting effect on Democrats. But drafting a plan that also tackles border security and could get the Senate — not to mention the president — on board will prove far more challenging.

What’s in the Dream and Promise Act

The Dream and Promise Act is essentially a more expansive version of the mainstay Democratic immigration bill the DREAM Act. While that bill covered mostly DREAMers, it did not address immigrants covered by Temporary Protected Status (TPS) or Deferred Enforced Departure (DED).

As Vox’s Dara Lind explained, the DREAM Act would have covered about 1.5 million immigrants; House Democrats’ latest version extends that by about 1 million people.

TPS recipients largely come from three countries: El Salvador, Honduras, and Haiti. Many of them have been living and working in the United States for decades, after fleeing their home countries due to natural disasters or political unrest. DED, meanwhile, mostly covers Liberian immigrants.

As Lind explained, all three groups of immigrants would eventually be allowed to apply for permanent legal status in the US under Democrats’ plan. But it would happen through different pathways and be a bit easier for humanitarian protectees:

The humanitarian protectees (TPS and DED holders) who’ve been in the US since fall 2016 would simply be allowed to apply for green cards (legal permanent residency), which they can’t do right now unless they qualify through other means. After having a green card for five years, they’d be allowed to apply for citizenship, just like any other green card holder.

DREAMers would have to demonstrate more things in order to get a green card, no matter if they were already in DACA. They would first have to apply for something called “conditional permanent residency,” which would only be granted under certain conditions.

As Lind laid out in her piece, the requirements include:

They would need to have arrived in the US before turning 18 and have been in the US for at least four years.

They would need a relatively clean record — a felony conviction or three separate misdemeanors involving total jail time of 90 days would be disqualifying.

They would need a high school diploma or GED, or to be enrolled in a program to get either one.

Finally, they would need to pass a background check and other eligibility requirements.

This “conditional status” designation would last for 10 years. But there would be other ways for DREAMers to be able to apply for a green card at any time, including serving in the military for two years, working for three years, or getting a degree from an institution of higher education (or be at least two years through a bachelor’s or technical program).

Democrats still need to tackle comprehensive immigration reform. They want to wait until Trump is out of office

Immigration reform has eluded Democrats and Republicans for decades, well before Trump was in office. Even agreement within a party has been difficult; immigration historically has been a thorny issue for Democrats. But with Trump in the White House, it has become a political lightning rod that has actually united Democrats — especially after a month-long government shutdown in January when Congress declined to give Trump his desired border wall money.

But Democrats still have to figure out what their comprehensive immigration policy will be, and that will be much more difficult than opposing Trump’s hardline policies. Notably, Democrats released their Department of Homeland Security funding bill on Tuesday, which provided no funding for a border wall, or additional border agents.

A pathway to citizenship for unauthorized immigrants is just part of what comprehensive immigration reform would entail. House Democrats’ bill is largely symbolic; all they can do is hope a Democrat gets elected to the White House in 2020, before they must start crafting a much bigger immigration bill.

“We’re sending out to members the different parts of a comprehensive bill that we think should be included, but the timeline obviously is a lot further out,” Congressional Hispanic Caucus Chair Joaquín Castro (D-TX) told Vox in March. “First, we’re going to get to the DREAM Act and TPS.”

The thornier issue Democrats need to agree on is border security — they know they don’t want Trump’s border wall, but they disagree on how much border security Democrats should offer up.

Democrats have a well-documented history of supporting physical barriers — just not Trump’s, as Vox’s Tara Golshan wrote in the middle of this year’s government shutdown. Customs and Border Protection spent $2.3 billion building and maintaining 654 miles of physical barriers on the southern border between 2007 and 2015, with the support of congressional Democrats.

A physical barrier is a cause of anger for the party’s base, but Democrats will likely have to strike some sort of deal on security eventually, especially if they want to push for legal protections for these three groups of immigrants.

That will be a much more difficult conversation to have, and Democrats would prefer to have it with Trump gone, so he doesn’t complicate the issue even further.