The status of almost 800,000 young undocumented immigrants brought to this country as minors by is now in the hands of the United States Supreme Court.

This is a story about the thwarted aspirations of two presidents to implement immigration reform. It is a story about presidents using the brute force of executive orders and directives in the face of congressional inaction.

This is a story about the thwarted aspirations of two presidents to implement immigration reform.

On Tuesday, the Supreme Court heard oral arguments in a case that asks whether President Donald Trump has adequately explained why he wants to end the Deferred Action for Childhood Arrivals (DACA) program created by President Barack Obama. After oral arguments, it seems likely that the case hinges on whether or not Chief Justice John Roberts believes the Trump administration's reasoning, with the rest of the justices lining up along ideological lines.

At issue is whether or not the Trump administration acted improperly in making the decision to end DACA back in 2017. If this sounds familiar, it is because this is the same question at issue in last year’s Supreme Court decision regarding the U.S. census. In that case, Roberts broke with his conservative colleagues to rebuke the Trump administration’s actions and a citizenship question was blocked. The question now is whether or not Roberts will break with his conservative colleagues again.

The broader desire to implement immigration reform has beguiled presidents for decades, however. In the first term of his presidency, President Barack Obama sought and failed to find a legislative solution to help the hundreds of thousands of young people living in the United States who were brought to this country when they were minors. Their stories are personal but their outcome is largely political. Many of these people have no memories or connections to the countries of their birth.

In 2012, foiled by a Republican-controlled Congress, Obama accomplished by executive order what he could not through the legislative process and created DACA. The program applies to people brought to this country before 2007, who have either served in the military or graduated from high school, and who have avoided any serious criminal convictions. People who qualify for DACA are often referred to as “Dreamers.”

In 2017, Trump, motivated by campaign promises and immigration hard-liners, announced plans to end DACA. But while Trump tried and failed to push Congress to find a legislative solution for the Dreamers, Congress, again, failed to act. Trump subsequently directed the Department of Homeland Security to end the program.

Importantly, these rulings don't mean that DACA will survive, only that the Trump administration must come up with a better way of ending it.

And here is where the courts became involved. All three federal trial court judges to rule on the ending of DACA said that the Trump administration could not simply end the program, at least not in the way the administration tried to end it. In all three cases, the courts of appeals agreed with those trial court decisions. Importantly, these rulings don't mean that DACA will survive, only that the Trump administration must come up with a better way of ending it.

The case now, as was largely inevitable, has landed before the Supreme Court. And the justices have been asked two questions. First, can judges even review the Homeland Security's decision to end DACA? Second, if they can, is the department's decision to end DACA legal?

The Trump administration’s first argument is that the decision is not judicially reviewable. The government’s second argument is that even if a judge can review the decision, DACA is likely an illegal program that cannot be maintained without violating federal immigration law. Further, the government argues that because DACA stands on, at best, shaky legal grounds, Republican states will soon be suing to invalidate DACA themselves. Therefore, it is better to just end it than wait for it to be declared invalid in court. (In addition, the government has argued that it must send a strong anti-illegal immigration message and that ending DACA will help to send that message.)

Those challenging Trump claim that Homeland Security's decision was based on a legal judgment, not a policy judgment, and is thus subject to judicial review. The challengers’ next argument is that the way the Trump administration tried to end DACA violates a federal law called the Administrative Procedure Act. The law requires that administrative agencies give a “satisfactory explanation for its action[s].” Challengers claim that the DHS failed to give such a reason, instead acting in a manner that was arbitrary and capricious.

Third, the challengers argue that DACA is a legal program. They point to the fact that the DHS has to prioritize whom it deports and when, and DACA is a proper way of allowing the DHS to exercise its authority to do that.

And finally, the challengers claim that the rights of the Dreamers will be violated if DACA ends. The challengers point to the harms caused by loss of employment, health care, and potentially deportation.

Given the questions in court Tuesday, the justices appear divided along ideological lines. Once again, all eyes are on the new middle of the Supreme Court — Roberts. It will be on Roberts’ shoulders to explain that federal law requiring federal agencies to give reasons for inactions still has meaning. It will be up to him to rein in the Trump administration.