This is the biggest cause of the shutdown. Ever since Trump announced in September that he would end the Obama-era Deferred Action for Childhood Arrivals program on March 5 unless Congress acted to extend it, Democrats in the House and Senate have been clamoring for a permanent legislative fix to protect the young immigrants known as Dreamers.
Prospects for a quick agreement brightened briefly in September after Trump appeared to sign off on a framework with Democratic leaders Nancy Pelosi and Charles Schumer; that plan would have traded the Dream Act for additional security at the border. But under pressure from immigration hard-liners, Trump backed away and added a whole new set of demands for a DACA deal, including funding for his border wall and significant changes to the legal immigration system.
Pelosi promised immigration activists that Democrats would not leave for the year without addressing DACA, but Senate Democrats agreed just before Christmas to punt the fight to January. With Friday’s funding deadline approaching and no immigration agreement in sight, Democrats in both the House and Senate this week decided to make a stand."