Trump’s first actions on immigration will likely be overturning the policies that US president Barack Obama put in place to protect undocumented immigrants.
Under the policy known as Deferred Action for Childhood Arrivals (DACA), implemented by Obama as an executive order in 2012, more than 700,000 immigrants who were brought into the country illegally as children have been allowed to temporarily stay and work in the US. DAPA is a similar policy for the undocumented parents of American citizens; it has been challenged in court by several states.
Trump has vowed to end DACA, DAPA, and so-called “catch-and-release” policies, or the practice of not detaining immigrants while they wait for their cases to be processed. He’s also said he’s going to triple the number of US Immigrations and Customs Enforcement agents and will “move criminal aliens out day one.”
None of this will result in mass deportations in the short term—the US Department of Homeland Security does not have the funding to deport all 11 million people who are thought to be in the country illegally, and it’s unclear where Trump would get it. There’s also a question of physical resources; thousand of Central American women and children who showed up at the border in the summer of 2014 quickly overwhelmed existing detention facilities.
It would take more funds still to build that wall between the US and Mexico that Trump has talked about from the start of his campaign. Aside from being very expensive, it would require congressional approval, and logistically, it would be very complicated to erect a barrier across the length of the entire border.