The Supreme Court announced yesterday that it will take up a lawsuit filed by Texas and 25 other states challenging President Obama’s executive action that would offer short-term protections for some classes of undocumented immigrants.

It’s a fight that immigration watchers have been raring for since Republicans filed a lawsuit challenging the program just weeks after Obama announced the program in November 2014. The initiative is called Deferred Action for Parents of Americans and Lawful Permanent Residents (DAPA), and would offer short-term deportation deferral to undocumented immigrants who have US-citizen or green card–holding children and who clear a host of other hurdles.

The program, which also included an expanded rollout of President Obama’s first executive action offering similar protections for young undocumented immigrants, has been on hold while the lawsuit has worked its way through the courts. Oral arguments are expected for April, with a ruling likely to come by late June, at the end of the Supreme Court’s current term and just weeks before the Democrats’ and Republicans’ nominating conventions.

DAPA marks the last viable option for immigration relief for even a subset of the nation’s estimated 11 million undocumented immigrants. As President Obama wraps up his last year in office, his passionate 2007 campaign promises to pass immigration reform still haunt him. They became the seeds for bitterness among immigrant communities who helped propel him to the presidency, and then waited through seven years of congressional inaction, alongside record-breaking deportations, with little in the way of relief to show for it.

As a result, DAPA has been politically charged from the start. As congressional deadlock killed off multiple attempts at immigration reform, President Obama turned to executive action in his second term to provide small but meaningful forms of relief for some classes of immigrants, including those who would have qualified for the DREAM Act, which narrowly failed to clear a Senate filibuster threat in 2010.

On the campaign trail, Republican candidates like Ted Cruz have vowed to end these programs, which exist and are extended at the discretion of the president. Marco Rubio, who is still fighting primary attacks over his work to support the Senate’s 2013 immigration reform bill, has vowed to also end deferred action if elected president. (One guess as to what seemingly indomitable front-runner Donald Trump would do.)

Democratic candidates, meanwhile, have pledged to stay to the left of President Obama. Even Hillary Clinton, the most conservative Democratic candidate, has vowed to preserve President Obama’s executive actions and “go further” than he did, by protecting other groups like the undocumented parents of those who immigrated to the country as children. Martin O’Malley and Bernie Sanders have offered even more generous promises to offer the similar short-term deportation shield to long-term undocumented immigrants who would have been eligible for the 2013 Senate bill. Indeed, promises to back comprehensive immigration reform, once a litmus test for pro-immigration voters, are the barest threshold for immigrant communities’ support today. Much more sought-after are promises that Democratic candidates will hold on to, and extend, President Obama’s executive actions.

All of these campaign promises are surely complicated by the Supreme Court’s review, which will consider whether states even have a right to interfere with the work of the executive branch. The case joins a full docket of other hot-button issues, including labor, abortion, and affirmative action.

Lower courts have sided with Texas and the other states on DAPA. But immigration activists applauded yesterday’s announcements, arguing that President Obama’s executive action relied on firmly established constitutional authority.