well, in short DACA was Obama's "Dreamers" act, Deferred Action for Childhood Arrivals. The DACA bill wasn't passed during Obama's last term, but during Trump's 1st term, the Democrats made this a big issue for illegal immigrant as a way for illegal immigrant children to be allowed in the U.S. even though their parents were not with them or didn't make it across the border. During the back and forth debate, the Democrats were demanding 750K illegal immigrant children be allowed to stay in the U.S. Eventually, Trump offered to double the amount to 1.5 million illegal immigrant children that could stay, but the Democrats refused to pass the bill. Trump basically exposed that the Democrats didn't really want to stop the flood of illegal immigrants.