This policy, announced by the Department of Homeland Security in 2012, came via a memorandum that directs authorities to exercise "prosecutorial discretion" in dealing with some young undocumented immigrants.
If they meet the criteria for eligibility, they are shielded temporarily from deportation and allowed to work. Critics say that waiving deportation laws for more than a million people is not "prosecutorial discretion" – it's policymaking by executive fiat, usurping the role of Congress. Defenders say DACA is an acceptable exampl of presidential discretion in policymaking.
Ten immigration agents challenged DACA in federal court, saying the policy undermined their duty to enforce the law. In 2013, the judge threw out the ecase on jurisdictional grounds, but suggested that DACA was inherently unlawful.
Politics also infused DACA. Obama was making a play for the Latino vote ahead of the 2012 election. Republican leaders, wary of alienating Latinos, chose not to challenge the policy.